Total Complexity | 614 |
Total Lines | 2243 |
Duplicated Lines | 1.69 % |
Changes | 0 |
Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like abydos.stemmer often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
1 | # -*- coding: utf-8 -*- |
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2 | |||
3 | # Copyright 2014-2018 by Christopher C. Little. |
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4 | # This file is part of Abydos. |
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5 | # |
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6 | # Abydos is free software: you can redistribute it and/or modify |
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7 | # it under the terms of the GNU General Public License as published by |
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8 | # the Free Software Foundation, either version 3 of the License, or |
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9 | # (at your option) any later version. |
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10 | # |
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11 | # Abydos is distributed in the hope that it will be useful, |
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12 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | # GNU General Public License for more details. |
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15 | # |
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16 | # You should have received a copy of the GNU General Public License |
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17 | # along with Abydos. If not, see <http://www.gnu.org/licenses/>. |
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18 | |||
19 | """abydos.stemmer. |
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20 | |||
21 | The stemmer module defines word stemmers including: |
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22 | |||
23 | - the Lovins stemmer |
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24 | - the Porter and Porter2 (Snowball English) stemmers |
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25 | - Snowball stemmers for German, Dutch, Norwegian, Swedish, and Danish |
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26 | - CLEF German, German plus, and Swedish stemmers |
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27 | - Caumann's German stemmer |
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28 | - UEA-Lite stemmer |
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29 | """ |
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30 | |||
31 | from __future__ import unicode_literals |
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32 | |||
33 | import re |
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34 | import unicodedata |
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35 | |||
36 | from six import text_type |
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37 | from six.moves import range |
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38 | |||
39 | |||
40 | def lovins(word): |
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41 | """Return Lovins stem. |
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42 | |||
43 | Lovins stemmer |
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44 | |||
45 | The Lovins stemmer is described in Julie Beth Lovins's article at: |
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46 | http://www.mt-archive.info/MT-1968-Lovins.pdf |
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47 | |||
48 | :param word: the word to stem |
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49 | :returns: word stem |
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50 | :rtype: string |
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51 | |||
52 | >>> lovins('reading') |
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53 | 'read' |
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54 | >>> lovins('suspension') |
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55 | 'suspens' |
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56 | >>> lovins('elusiveness') |
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57 | 'elus' |
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58 | """ |
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59 | # pylint: disable=too-many-branches, too-many-locals |
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60 | |||
61 | # lowercase, normalize, and compose |
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62 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
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63 | |||
64 | def cond_b(word, suffix_len): |
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65 | """Return Lovins' condition B.""" |
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66 | return len(word)-suffix_len >= 3 |
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67 | |||
68 | def cond_c(word, suffix_len): |
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69 | """Return Lovins' condition C.""" |
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70 | return len(word)-suffix_len >= 4 |
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71 | |||
72 | def cond_d(word, suffix_len): |
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73 | """Return Lovins' condition D.""" |
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74 | return len(word)-suffix_len >= 5 |
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75 | |||
76 | def cond_e(word, suffix_len): |
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77 | """Return Lovins' condition E.""" |
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78 | return word[-suffix_len-1] != 'e' |
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79 | |||
80 | def cond_f(word, suffix_len): |
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81 | """Return Lovins' condition F.""" |
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82 | return (len(word)-suffix_len >= 3 and |
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83 | word[-suffix_len-1] != 'e') |
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84 | |||
85 | def cond_g(word, suffix_len): |
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86 | """Return Lovins' condition G.""" |
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87 | return (len(word)-suffix_len >= 3 and |
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88 | word[-suffix_len-1] == 'f') |
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89 | |||
90 | def cond_h(word, suffix_len): |
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91 | """Return Lovins' condition H.""" |
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92 | return (word[-suffix_len-1] == 't' or |
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93 | word[-suffix_len-2:-suffix_len] == 'll') |
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94 | |||
95 | def cond_i(word, suffix_len): |
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96 | """Return Lovins' condition I.""" |
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97 | return word[-suffix_len-1] not in {'e', 'o'} |
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98 | |||
99 | def cond_j(word, suffix_len): |
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100 | """Return Lovins' condition J.""" |
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101 | return word[-suffix_len-1] not in {'a', 'e'} |
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102 | |||
103 | def cond_k(word, suffix_len): |
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104 | """Return Lovins' condition K.""" |
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105 | return (len(word)-suffix_len >= 3 and |
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106 | (word[-suffix_len-1] in {'i', 'l'} or |
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107 | (word[-suffix_len-3] == 'u' and word[-suffix_len-1] == 'e'))) |
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108 | |||
109 | def cond_l(word, suffix_len): |
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110 | """Return Lovins' condition L.""" |
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111 | return (word[-suffix_len-1] not in {'s', 'u', 'x'} or |
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112 | word[-suffix_len-1] == 'os') |
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113 | |||
114 | def cond_m(word, suffix_len): |
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115 | """Return Lovins' condition M.""" |
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116 | return word[-suffix_len-1] not in {'a', 'c', 'e', 'm'} |
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117 | |||
118 | def cond_n(word, suffix_len): |
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119 | """Return Lovins' condition N.""" |
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120 | if len(word)-suffix_len >= 3: |
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121 | if word[-suffix_len-3] == 's': |
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122 | if len(word)-suffix_len >= 4: |
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123 | return True |
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124 | else: |
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125 | return True |
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126 | return False |
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127 | |||
128 | def cond_o(word, suffix_len): |
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129 | """Return Lovins' condition O.""" |
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130 | return word[-suffix_len-1] in {'i', 'l'} |
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131 | |||
132 | def cond_p(word, suffix_len): |
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133 | """Return Lovins' condition P.""" |
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134 | return word[-suffix_len-1] != 'c' |
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135 | |||
136 | def cond_q(word, suffix_len): |
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137 | """Return Lovins' condition Q.""" |
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138 | return (len(word)-suffix_len >= 3 and |
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139 | word[-suffix_len-1] not in {'l', 'n'}) |
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140 | |||
141 | def cond_r(word, suffix_len): |
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142 | """Return Lovins' condition R.""" |
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143 | return word[-suffix_len-1] in {'n', 'r'} |
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144 | |||
145 | def cond_s(word, suffix_len): |
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146 | """Return Lovins' condition S.""" |
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147 | return (word[-suffix_len-2:-suffix_len] == 'dr' or |
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148 | (word[-suffix_len-1] == 't' and |
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149 | word[-suffix_len-2:-suffix_len] != 'tt')) |
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150 | |||
151 | def cond_t(word, suffix_len): |
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152 | """Return Lovins' condition T.""" |
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153 | return (word[-suffix_len-1] in {'s', 't'} and |
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154 | word[-suffix_len-2:-suffix_len] != 'ot') |
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155 | |||
156 | def cond_u(word, suffix_len): |
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157 | """Return Lovins' condition U.""" |
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158 | return word[-suffix_len-1] in {'l', 'm', 'n', 'r'} |
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159 | |||
160 | def cond_v(word, suffix_len): |
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161 | """Return Lovins' condition V.""" |
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162 | return word[-suffix_len-1] == 'c' |
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163 | |||
164 | def cond_w(word, suffix_len): |
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165 | """Return Lovins' condition W.""" |
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166 | return word[-suffix_len-1] not in {'s', 'u'} |
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167 | |||
168 | def cond_x(word, suffix_len): |
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169 | """Return Lovins' condition X.""" |
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170 | return (word[-suffix_len-1] in {'i', 'l'} or |
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171 | (word[-suffix_len-3:-suffix_len] == 'u' and |
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172 | word[-suffix_len-1] == 'e')) |
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173 | |||
174 | def cond_y(word, suffix_len): |
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175 | """Return Lovins' condition Y.""" |
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176 | return word[-suffix_len-2:-suffix_len] == 'in' |
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177 | |||
178 | def cond_z(word, suffix_len): |
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179 | """Return Lovins' condition Z.""" |
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180 | return word[-suffix_len-1] != 'f' |
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181 | |||
182 | def cond_aa(word, suffix_len): |
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183 | """Return Lovins' condition AA.""" |
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184 | return (word[-suffix_len-1] in {'d', 'f', 'l', 't'} or |
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185 | word[-suffix_len-2:-suffix_len] in {'ph', 'th', 'er', 'or', |
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186 | 'es'}) |
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187 | |||
188 | def cond_bb(word, suffix_len): |
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189 | """Return Lovins' condition BB.""" |
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190 | return (len(word)-suffix_len >= 3 and |
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191 | word[-suffix_len-3:-suffix_len] != 'met' and |
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192 | word[-suffix_len-4:-suffix_len] != 'ryst') |
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193 | |||
194 | def cond_cc(word, suffix_len): |
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195 | """Return Lovins' condition CC.""" |
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196 | return word[-suffix_len-1] == 'l' |
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197 | |||
198 | suffix = {'alistically': cond_b, 'arizability': None, |
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199 | 'izationally': cond_b, 'antialness': None, |
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200 | 'arisations': None, 'arizations': None, 'entialness': None, |
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201 | 'allically': cond_c, 'antaneous': None, 'antiality': None, |
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202 | 'arisation': None, 'arization': None, 'ationally': cond_b, |
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203 | 'ativeness': None, 'eableness': cond_e, 'entations': None, |
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204 | 'entiality': None, 'entialize': None, 'entiation': None, |
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205 | 'ionalness': None, 'istically': None, 'itousness': None, |
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206 | 'izability': None, 'izational': None, 'ableness': None, |
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207 | 'arizable': None, 'entation': None, 'entially': None, |
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208 | 'eousness': None, 'ibleness': None, 'icalness': None, |
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209 | 'ionalism': None, 'ionality': None, 'ionalize': None, |
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210 | 'iousness': None, 'izations': None, 'lessness': None, |
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211 | 'ability': None, 'aically': None, 'alistic': cond_b, |
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212 | 'alities': None, 'ariness': cond_e, 'aristic': None, |
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213 | 'arizing': None, 'ateness': None, 'atingly': None, |
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214 | 'ational': cond_b, 'atively': None, 'ativism': None, |
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215 | 'elihood': cond_e, 'encible': None, 'entally': None, |
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216 | 'entials': None, 'entiate': None, 'entness': None, |
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217 | 'fulness': None, 'ibility': None, 'icalism': None, |
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218 | 'icalist': None, 'icality': None, 'icalize': None, |
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219 | 'ication': cond_g, 'icianry': None, 'ination': None, |
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220 | 'ingness': None, 'ionally': None, 'isation': None, |
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221 | 'ishness': None, 'istical': None, 'iteness': None, |
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222 | 'iveness': None, 'ivistic': None, 'ivities': None, |
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223 | 'ization': cond_f, 'izement': None, 'oidally': None, |
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224 | 'ousness': None, 'aceous': None, 'acious': cond_b, |
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225 | 'action': cond_g, 'alness': None, 'ancial': None, |
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226 | 'ancies': None, 'ancing': cond_b, 'ariser': None, |
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227 | 'arized': None, 'arizer': None, 'atable': None, |
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228 | 'ations': cond_b, 'atives': None, 'eature': cond_z, |
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229 | 'efully': None, 'encies': None, 'encing': None, |
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230 | 'ential': None, 'enting': cond_c, 'entist': None, |
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231 | 'eously': None, 'ialist': None, 'iality': None, |
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232 | 'ialize': None, 'ically': None, 'icance': None, |
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233 | 'icians': None, 'icists': None, 'ifully': None, |
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234 | 'ionals': None, 'ionate': cond_d, 'ioning': None, |
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235 | 'ionist': None, 'iously': None, 'istics': None, |
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236 | 'izable': cond_e, 'lessly': None, 'nesses': None, |
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237 | 'oidism': None, 'acies': None, 'acity': None, |
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238 | 'aging': cond_b, 'aical': None, 'alist': None, |
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239 | 'alism': cond_b, 'ality': None, 'alize': None, |
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240 | 'allic': cond_bb, 'anced': cond_b, 'ances': cond_b, |
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241 | 'antic': cond_c, 'arial': None, 'aries': None, |
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242 | 'arily': None, 'arity': cond_b, 'arize': None, |
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243 | 'aroid': None, 'ately': None, 'ating': cond_i, |
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244 | 'ation': cond_b, 'ative': None, 'ators': None, |
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245 | 'atory': None, 'ature': cond_e, 'early': cond_y, |
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246 | 'ehood': None, 'eless': None, 'elity': None, |
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247 | 'ement': None, 'enced': None, 'ences': None, |
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248 | 'eness': cond_e, 'ening': cond_e, 'ental': None, |
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249 | 'ented': cond_c, 'ently': None, 'fully': None, |
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250 | 'ially': None, 'icant': None, 'ician': None, |
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251 | 'icide': None, 'icism': None, 'icist': None, |
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252 | 'icity': None, 'idine': cond_i, 'iedly': None, |
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253 | 'ihood': None, 'inate': None, 'iness': None, |
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254 | 'ingly': cond_b, 'inism': cond_j, 'inity': cond_cc, |
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255 | 'ional': None, 'ioned': None, 'ished': None, |
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256 | 'istic': None, 'ities': None, 'itous': None, |
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257 | 'ively': None, 'ivity': None, 'izers': cond_f, |
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258 | 'izing': cond_f, 'oidal': None, 'oides': None, |
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259 | 'otide': None, 'ously': None, 'able': None, 'ably': None, |
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260 | 'ages': cond_b, 'ally': cond_b, 'ance': cond_b, 'ancy': cond_b, |
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261 | 'ants': cond_b, 'aric': None, 'arly': cond_k, 'ated': cond_i, |
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262 | 'ates': None, 'atic': cond_b, 'ator': None, 'ealy': cond_y, |
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263 | 'edly': cond_e, 'eful': None, 'eity': None, 'ence': None, |
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264 | 'ency': None, 'ened': cond_e, 'enly': cond_e, 'eous': None, |
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265 | 'hood': None, 'ials': None, 'ians': None, 'ible': None, |
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266 | 'ibly': None, 'ical': None, 'ides': cond_l, 'iers': None, |
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267 | 'iful': None, 'ines': cond_m, 'ings': cond_n, 'ions': cond_b, |
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268 | 'ious': None, 'isms': cond_b, 'ists': None, 'itic': cond_h, |
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269 | 'ized': cond_f, 'izer': cond_f, 'less': None, 'lily': None, |
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270 | 'ness': None, 'ogen': None, 'ward': None, 'wise': None, |
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271 | 'ying': cond_b, 'yish': None, 'acy': None, 'age': cond_b, |
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272 | 'aic': None, 'als': cond_bb, 'ant': cond_b, 'ars': cond_o, |
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273 | 'ary': cond_f, 'ata': None, 'ate': None, 'eal': cond_y, |
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274 | 'ear': cond_y, 'ely': cond_e, 'ene': cond_e, 'ent': cond_c, |
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275 | 'ery': cond_e, 'ese': None, 'ful': None, 'ial': None, |
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276 | 'ian': None, 'ics': None, 'ide': cond_l, 'ied': None, |
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277 | 'ier': None, 'ies': cond_p, 'ily': None, 'ine': cond_m, |
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278 | 'ing': cond_n, 'ion': cond_q, 'ish': cond_c, 'ism': cond_b, |
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279 | 'ist': None, 'ite': cond_aa, 'ity': None, 'ium': None, |
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280 | 'ive': None, 'ize': cond_f, 'oid': None, 'one': cond_r, |
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281 | 'ous': None, 'ae': None, 'al': cond_bb, 'ar': cond_x, |
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282 | 'as': cond_b, 'ed': cond_e, 'en': cond_f, 'es': cond_e, |
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283 | 'ia': None, 'ic': None, 'is': None, 'ly': cond_b, |
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284 | 'on': cond_s, 'or': cond_t, 'um': cond_u, 'us': cond_v, |
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285 | 'yl': cond_r, '\'s': None, 's\'': None, 'a': None, |
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286 | 'e': None, 'i': None, 'o': None, 's': cond_w, 'y': cond_b} |
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287 | |||
288 | for suffix_len in range(11, 0, -1): |
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289 | ending = word[-suffix_len:] |
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290 | if (ending in suffix and |
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291 | len(word)-suffix_len >= 2 and |
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292 | (suffix[ending] is None or |
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293 | suffix[ending](word, suffix_len))): |
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294 | word = word[:-suffix_len] |
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295 | break |
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296 | |||
297 | def recode9(stem): |
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298 | """Return Lovins' conditional recode rule 9.""" |
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299 | if stem[-3:-2] in {'a', 'i', 'o'}: |
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300 | return stem |
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301 | return stem[:-2]+'l' |
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302 | |||
303 | def recode24(stem): |
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304 | """Return Lovins' conditional recode rule 24.""" |
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305 | if stem[-4:-3] == 's': |
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306 | return stem |
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307 | return stem[:-1]+'s' |
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308 | |||
309 | def recode28(stem): |
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310 | """Return Lovins' conditional recode rule 28.""" |
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311 | if stem[-4:-3] in {'p', 't'}: |
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312 | return stem |
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313 | return stem[:-1]+'s' |
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314 | |||
315 | def recode30(stem): |
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316 | """Return Lovins' conditional recode rule 30.""" |
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317 | if stem[-4:-3] == 'm': |
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318 | return stem |
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319 | return stem[:-1]+'s' |
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320 | |||
321 | def recode32(stem): |
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322 | """Return Lovins' conditional recode rule 32.""" |
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323 | if stem[-3:-2] == 'n': |
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324 | return stem |
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325 | return stem[:-1]+'s' |
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326 | |||
327 | if word[-2:] in {'bb', 'dd', 'gg', 'll', 'mm', 'nn', 'pp', 'rr', 'ss', |
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328 | 'tt'}: |
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329 | word = word[:-1] |
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330 | |||
331 | recode = (('iev', 'ief'), |
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332 | ('uct', 'uc'), |
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333 | ('umpt', 'um'), |
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334 | ('rpt', 'rb'), |
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335 | ('urs', 'ur'), |
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336 | ('istr', 'ister'), |
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337 | ('metr', 'meter'), |
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338 | ('olv', 'olut'), |
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339 | ('ul', recode9), |
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340 | ('bex', 'bic'), |
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341 | ('dex', 'dic'), |
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342 | ('pex', 'pic'), |
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343 | ('tex', 'tic'), |
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344 | ('ax', 'ac'), |
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345 | ('ex', 'ec'), |
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346 | ('ix', 'ic'), |
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347 | ('lux', 'luc'), |
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348 | ('uad', 'uas'), |
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349 | ('vad', 'vas'), |
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350 | ('cid', 'cis'), |
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351 | ('lid', 'lis'), |
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352 | ('erid', 'eris'), |
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353 | ('pand', 'pans'), |
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354 | ('end', recode24), |
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355 | ('ond', 'ons'), |
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356 | ('lud', 'lus'), |
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357 | ('rud', 'rus'), |
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358 | ('her', recode28), |
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359 | ('mit', 'mis'), |
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360 | ('ent', recode30), |
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361 | ('ert', 'ers'), |
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362 | ('et', recode32), |
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363 | ('yt', 'ys'), |
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364 | ('yz', 'ys')) |
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365 | |||
366 | for ending, replacement in recode: |
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367 | if word.endswith(ending): |
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368 | if callable(replacement): |
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369 | word = replacement(word) |
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370 | else: |
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371 | word = word[:-len(ending)] + replacement |
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372 | |||
373 | return word |
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374 | |||
375 | |||
376 | def _m_degree(term, vowels): |
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377 | """Return Porter helper function _m_degree value. |
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378 | |||
379 | m-degree is equal to the number of V to C transitions |
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380 | |||
381 | :param term: the word for which to calculate the m-degree |
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382 | :param vowels: the set of vowels in the language |
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383 | :returns: the m-degree as defined in the Porter stemmer definition |
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384 | """ |
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385 | mdeg = 0 |
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386 | last_was_vowel = False |
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387 | for letter in term: |
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388 | if letter in vowels: |
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389 | last_was_vowel = True |
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390 | else: |
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391 | if last_was_vowel: |
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392 | mdeg += 1 |
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393 | last_was_vowel = False |
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394 | return mdeg |
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395 | |||
396 | |||
397 | def _sb_has_vowel(term, vowels): |
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398 | """Return Porter helper function _sb_has_vowel value. |
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399 | |||
400 | :param term: the word to scan for vowels |
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401 | :param vowels: the set of vowels in the language |
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402 | :returns: true iff a vowel exists in the term (as defined in the Porter |
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403 | stemmer definition) |
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404 | """ |
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405 | for letter in term: |
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406 | if letter in vowels: |
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407 | return True |
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408 | return False |
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409 | |||
410 | |||
411 | def _ends_in_doubled_cons(term, vowels): |
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412 | """Return Porter helper function _ends_in_doubled_cons value. |
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413 | |||
414 | :param term: the word to check for a final doubled consonant |
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415 | :param vowels: the set of vowels in the language |
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416 | :returns: true iff the stem ends in a doubled consonant (as defined in the |
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417 | Porter stemmer definition) |
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418 | """ |
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419 | if len(term) > 1 and term[-1] not in vowels and term[-2] == term[-1]: |
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420 | return True |
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421 | return False |
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422 | |||
423 | |||
424 | def _ends_in_cvc(term, vowels): |
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425 | """Return Porter helper function _ends_in_cvc value. |
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426 | |||
427 | :param term: the word to scan for cvc |
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428 | :param vowels: the set of vowels in the language |
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429 | :returns: true iff the stem ends in cvc (as defined in the Porter stemmer |
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430 | definition) |
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431 | """ |
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432 | if len(term) > 2 and (term[-1] not in vowels and |
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433 | term[-2] in vowels and |
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434 | term[-3] not in vowels and |
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435 | term[-1] not in tuple('wxY')): |
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436 | return True |
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437 | return False |
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438 | |||
439 | |||
440 | def porter(word, early_english=False): |
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441 | """Return Porter stem. |
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442 | |||
443 | The Porter stemmer is defined at: |
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444 | http://snowball.tartarus.org/algorithms/porter/stemmer.html |
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445 | |||
446 | :param word: the word to calculate the stem of |
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447 | :param early_english: set to True in order to remove -eth & -est (2nd & 3rd |
||
448 | person singular verbal agreement suffixes) |
||
449 | :returns: word stem |
||
450 | :rtype: str |
||
451 | |||
452 | >>> porter('reading') |
||
453 | 'read' |
||
454 | >>> porter('suspension') |
||
455 | 'suspens' |
||
456 | >>> porter('elusiveness') |
||
457 | 'elus' |
||
458 | |||
459 | >>> porter('eateth', early_english=True) |
||
460 | 'eat' |
||
461 | """ |
||
462 | # pylint: disable=too-many-branches |
||
463 | |||
464 | # lowercase, normalize, and compose |
||
465 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
466 | |||
467 | # Return word if stem is shorter than 2 |
||
468 | if len(word) < 3: |
||
469 | return word |
||
470 | |||
471 | _vowels = {'a', 'e', 'i', 'o', 'u', 'y'} |
||
472 | # Re-map consonantal y to Y (Y will be C, y will be V) |
||
473 | if word[0] == 'y': |
||
474 | word = 'Y' + word[1:] |
||
475 | for i in range(1, len(word)): |
||
476 | if word[i] == 'y' and word[i-1] in _vowels: |
||
477 | word = word[:i] + 'Y' + word[i+1:] |
||
478 | |||
479 | # Step 1a |
||
480 | if word[-1] == 's': |
||
481 | if word[-4:] == 'sses': |
||
482 | word = word[:-2] |
||
483 | elif word[-3:] == 'ies': |
||
484 | word = word[:-2] |
||
485 | elif word[-2:] == 'ss': |
||
486 | pass |
||
487 | else: |
||
488 | word = word[:-1] |
||
489 | |||
490 | # Step 1b |
||
491 | step1b_flag = False |
||
492 | if word[-3:] == 'eed': |
||
493 | if _m_degree(word[:-3], _vowels) > 0: |
||
494 | word = word[:-1] |
||
495 | elif word[-2:] == 'ed': |
||
496 | if _sb_has_vowel(word[:-2], _vowels): |
||
497 | word = word[:-2] |
||
498 | step1b_flag = True |
||
499 | elif word[-3:] == 'ing': |
||
500 | if _sb_has_vowel(word[:-3], _vowels): |
||
501 | word = word[:-3] |
||
502 | step1b_flag = True |
||
503 | elif early_english: |
||
504 | if word[-3:] == 'est': |
||
505 | if _sb_has_vowel(word[:-3], _vowels): |
||
506 | word = word[:-3] |
||
507 | step1b_flag = True |
||
508 | elif word[-3:] == 'eth': |
||
509 | if _sb_has_vowel(word[:-3], _vowels): |
||
510 | word = word[:-3] |
||
511 | step1b_flag = True |
||
512 | |||
513 | if step1b_flag: |
||
514 | if word[-2:] in {'at', 'bl', 'iz'}: |
||
515 | word += 'e' |
||
516 | elif (_ends_in_doubled_cons(word, _vowels) and |
||
517 | word[-1] not in {'l', 's', 'z'}): |
||
518 | word = word[:-1] |
||
519 | elif _m_degree(word, _vowels) == 1 and _ends_in_cvc(word, _vowels): |
||
520 | word += 'e' |
||
521 | |||
522 | # Step 1c |
||
523 | if word[-1] in {'Y', 'y'} and _sb_has_vowel(word[:-1], _vowels): |
||
524 | word = word[:-1] + 'i' |
||
525 | |||
526 | # Step 2 |
||
527 | if len(word) > 1: |
||
528 | if word[-2] == 'a': |
||
529 | if word[-7:] == 'ational': |
||
530 | if _m_degree(word[:-7], _vowels) > 0: |
||
531 | word = word[:-5] + 'e' |
||
532 | elif word[-6:] == 'tional': |
||
533 | if _m_degree(word[:-6], _vowels) > 0: |
||
534 | word = word[:-2] |
||
535 | elif word[-2] == 'c': |
||
536 | if word[-4:] in {'enci', 'anci'}: |
||
537 | if _m_degree(word[:-4], _vowels) > 0: |
||
538 | word = word[:-1] + 'e' |
||
539 | elif word[-2] == 'e': |
||
540 | if word[-4:] == 'izer': |
||
541 | if _m_degree(word[:-4], _vowels) > 0: |
||
542 | word = word[:-1] |
||
543 | elif word[-2] == 'g': |
||
544 | if word[-4:] == 'logi': |
||
545 | if _m_degree(word[:-4], _vowels) > 0: |
||
546 | word = word[:-1] |
||
547 | elif word[-2] == 'l': |
||
548 | if word[-3:] == 'bli': |
||
549 | if _m_degree(word[:-3], _vowels) > 0: |
||
550 | word = word[:-1] + 'e' |
||
551 | elif word[-4:] == 'alli': |
||
552 | if _m_degree(word[:-4], _vowels) > 0: |
||
553 | word = word[:-2] |
||
554 | elif word[-5:] == 'entli': |
||
555 | if _m_degree(word[:-5], _vowels) > 0: |
||
556 | word = word[:-2] |
||
557 | elif word[-3:] == 'eli': |
||
558 | if _m_degree(word[:-3], _vowels) > 0: |
||
559 | word = word[:-2] |
||
560 | elif word[-5:] == 'ousli': |
||
561 | if _m_degree(word[:-5], _vowels) > 0: |
||
562 | word = word[:-2] |
||
563 | elif word[-2] == 'o': |
||
564 | if word[-7:] == 'ization': |
||
565 | if _m_degree(word[:-7], _vowels) > 0: |
||
566 | word = word[:-5] + 'e' |
||
567 | elif word[-5:] == 'ation': |
||
568 | if _m_degree(word[:-5], _vowels) > 0: |
||
569 | word = word[:-3] + 'e' |
||
570 | elif word[-4:] == 'ator': |
||
571 | if _m_degree(word[:-4], _vowels) > 0: |
||
572 | word = word[:-2] + 'e' |
||
573 | elif word[-2] == 's': |
||
574 | if word[-5:] == 'alism': |
||
575 | if _m_degree(word[:-5], _vowels) > 0: |
||
576 | word = word[:-3] |
||
577 | elif word[-7:] in {'iveness', 'fulness', 'ousness'}: |
||
578 | if _m_degree(word[:-7], _vowels) > 0: |
||
579 | word = word[:-4] |
||
580 | elif word[-2] == 't': |
||
581 | if word[-5:] == 'aliti': |
||
582 | if _m_degree(word[:-5], _vowels) > 0: |
||
583 | word = word[:-3] |
||
584 | elif word[-5:] == 'iviti': |
||
585 | if _m_degree(word[:-5], _vowels) > 0: |
||
586 | word = word[:-3] + 'e' |
||
587 | elif word[-6:] == 'biliti': |
||
588 | if _m_degree(word[:-6], _vowels) > 0: |
||
589 | word = word[:-5] + 'le' |
||
590 | |||
591 | # Step 3 |
||
592 | if word[-5:] == 'icate': |
||
593 | if _m_degree(word[:-5], _vowels) > 0: |
||
594 | word = word[:-3] |
||
595 | elif word[-5:] == 'ative': |
||
596 | if _m_degree(word[:-5], _vowels) > 0: |
||
597 | word = word[:-5] |
||
598 | elif word[-5:] in {'alize', 'iciti'}: |
||
599 | if _m_degree(word[:-5], _vowels) > 0: |
||
600 | word = word[:-3] |
||
601 | elif word[-4:] == 'ical': |
||
602 | if _m_degree(word[:-4], _vowels) > 0: |
||
603 | word = word[:-2] |
||
604 | elif word[-3:] == 'ful': |
||
605 | if _m_degree(word[:-3], _vowels) > 0: |
||
606 | word = word[:-3] |
||
607 | elif word[-4:] == 'ness': |
||
608 | if _m_degree(word[:-4], _vowels) > 0: |
||
609 | word = word[:-4] |
||
610 | |||
611 | # Step 4 |
||
612 | if word[-2:] == 'al': |
||
613 | if _m_degree(word[:-2], _vowels) > 1: |
||
614 | word = word[:-2] |
||
615 | elif word[-4:] == 'ance': |
||
616 | if _m_degree(word[:-4], _vowels) > 1: |
||
617 | word = word[:-4] |
||
618 | elif word[-4:] == 'ence': |
||
619 | if _m_degree(word[:-4], _vowels) > 1: |
||
620 | word = word[:-4] |
||
621 | elif word[-2:] == 'er': |
||
622 | if _m_degree(word[:-2], _vowels) > 1: |
||
623 | word = word[:-2] |
||
624 | elif word[-2:] == 'ic': |
||
625 | if _m_degree(word[:-2], _vowels) > 1: |
||
626 | word = word[:-2] |
||
627 | elif word[-4:] == 'able': |
||
628 | if _m_degree(word[:-4], _vowels) > 1: |
||
629 | word = word[:-4] |
||
630 | elif word[-4:] == 'ible': |
||
631 | if _m_degree(word[:-4], _vowels) > 1: |
||
632 | word = word[:-4] |
||
633 | elif word[-3:] == 'ant': |
||
634 | if _m_degree(word[:-3], _vowels) > 1: |
||
635 | word = word[:-3] |
||
636 | elif word[-5:] == 'ement': |
||
637 | if _m_degree(word[:-5], _vowels) > 1: |
||
638 | word = word[:-5] |
||
639 | elif word[-4:] == 'ment': |
||
640 | if _m_degree(word[:-4], _vowels) > 1: |
||
641 | word = word[:-4] |
||
642 | elif word[-3:] == 'ent': |
||
643 | if _m_degree(word[:-3], _vowels) > 1: |
||
644 | word = word[:-3] |
||
645 | elif word[-4:] in {'sion', 'tion'}: |
||
646 | if _m_degree(word[:-3], _vowels) > 1: |
||
647 | word = word[:-3] |
||
648 | elif word[-2:] == 'ou': |
||
649 | if _m_degree(word[:-2], _vowels) > 1: |
||
650 | word = word[:-2] |
||
651 | elif word[-3:] == 'ism': |
||
652 | if _m_degree(word[:-3], _vowels) > 1: |
||
653 | word = word[:-3] |
||
654 | elif word[-3:] == 'ate': |
||
655 | if _m_degree(word[:-3], _vowels) > 1: |
||
656 | word = word[:-3] |
||
657 | elif word[-3:] == 'iti': |
||
658 | if _m_degree(word[:-3], _vowels) > 1: |
||
659 | word = word[:-3] |
||
660 | elif word[-3:] == 'ous': |
||
661 | if _m_degree(word[:-3], _vowels) > 1: |
||
662 | word = word[:-3] |
||
663 | elif word[-3:] == 'ive': |
||
664 | if _m_degree(word[:-3], _vowels) > 1: |
||
665 | word = word[:-3] |
||
666 | elif word[-3:] == 'ize': |
||
667 | if _m_degree(word[:-3], _vowels) > 1: |
||
668 | word = word[:-3] |
||
669 | |||
670 | # Step 5a |
||
671 | if word[-1] == 'e': |
||
672 | if _m_degree(word[:-1], _vowels) > 1: |
||
673 | word = word[:-1] |
||
674 | elif (_m_degree(word[:-1], _vowels) == 1 and |
||
675 | not _ends_in_cvc(word[:-1], _vowels)): |
||
676 | word = word[:-1] |
||
677 | |||
678 | # Step 5b |
||
679 | if word[-2:] == 'll' and _m_degree(word, _vowels) > 1: |
||
680 | word = word[:-1] |
||
681 | |||
682 | # Change 'Y' back to 'y' if it survived stemming |
||
683 | for i in range(len(word)): |
||
684 | if word[i] == 'Y': |
||
685 | word = word[:i] + 'y' + word[i+1:] |
||
686 | |||
687 | return word |
||
688 | |||
689 | |||
690 | def _sb_r1(term, vowels, r1_prefixes=None): |
||
691 | """Return the R1 region, as defined in the Porter2 specification.""" |
||
692 | vowel_found = False |
||
693 | if hasattr(r1_prefixes, '__iter__'): |
||
694 | for prefix in r1_prefixes: |
||
695 | if term[:len(prefix)] == prefix: |
||
696 | return len(prefix) |
||
697 | |||
698 | for i in range(len(term)): |
||
699 | if not vowel_found and term[i] in vowels: |
||
700 | vowel_found = True |
||
701 | elif vowel_found and term[i] not in vowels: |
||
702 | return i + 1 |
||
703 | return len(term) |
||
704 | |||
705 | |||
706 | def _sb_r2(term, vowels, r1_prefixes=None): |
||
707 | """Return the R2 region, as defined in the Porter2 specification.""" |
||
708 | r1_start = _sb_r1(term, vowels, r1_prefixes) |
||
709 | return r1_start + _sb_r1(term[r1_start:], vowels) |
||
710 | |||
711 | |||
712 | def _sb_ends_in_short_syllable(term, vowels, codanonvowels): |
||
713 | """Return True iff term ends in a short syllable. |
||
714 | |||
715 | (...according to the Porter2 specification.) |
||
716 | |||
717 | NB: This is akin to the CVC test from the Porter stemmer. The description |
||
718 | is unfortunately poor/ambiguous. |
||
719 | """ |
||
720 | if not term: |
||
721 | return False |
||
722 | if len(term) == 2: |
||
723 | if term[-2] in vowels and term[-1] not in vowels: |
||
724 | return True |
||
725 | elif len(term) >= 3: |
||
726 | if ((term[-3] not in vowels and term[-2] in vowels and |
||
727 | term[-1] in codanonvowels)): |
||
728 | return True |
||
729 | return False |
||
730 | |||
731 | |||
732 | def _sb_short_word(term, vowels, codanonvowels, r1_prefixes=None): |
||
733 | """Return True iff term is a short word. |
||
734 | |||
735 | (...according to the Porter2 specification.) |
||
736 | """ |
||
737 | if ((_sb_r1(term, vowels, r1_prefixes) == len(term) and |
||
738 | _sb_ends_in_short_syllable(term, vowels, codanonvowels))): |
||
739 | return True |
||
740 | return False |
||
741 | |||
742 | |||
743 | def porter2(word, early_english=False): |
||
744 | """Return the Porter2 (Snowball English) stem. |
||
745 | |||
746 | The Porter2 (Snowball English) stemmer is defined at: |
||
747 | http://snowball.tartarus.org/algorithms/english/stemmer.html |
||
748 | |||
749 | :param word: the word to calculate the stem of |
||
750 | :param early_english: set to True in order to remove -eth & -est (2nd & 3rd |
||
751 | person singular verbal agreement suffixes) |
||
752 | :returns: word stem |
||
753 | :rtype: str |
||
754 | |||
755 | >>> porter2('reading') |
||
756 | 'read' |
||
757 | >>> porter2('suspension') |
||
758 | 'suspens' |
||
759 | >>> porter2('elusiveness') |
||
760 | 'elus' |
||
761 | |||
762 | >>> porter2('eateth', early_english=True) |
||
763 | 'eat' |
||
764 | """ |
||
765 | # pylint: disable=too-many-branches |
||
766 | # pylint: disable=too-many-return-statements |
||
767 | |||
768 | _vowels = {'a', 'e', 'i', 'o', 'u', 'y'} |
||
769 | _codanonvowels = {"'", 'b', 'c', 'd', 'f', 'g', 'h', 'j', 'k', 'l', 'm', |
||
770 | 'n', 'p', 'q', 'r', 's', 't', 'v', 'z'} |
||
771 | _doubles = {'bb', 'dd', 'ff', 'gg', 'mm', 'nn', 'pp', 'rr', 'tt'} |
||
772 | _li = {'c', 'd', 'e', 'g', 'h', 'k', 'm', 'n', 'r', 't'} |
||
773 | |||
774 | # R1 prefixes should be in order from longest to shortest to prevent |
||
775 | # masking |
||
776 | _r1_prefixes = ('commun', 'gener', 'arsen') |
||
777 | _exception1dict = { # special changes: |
||
778 | 'skis': 'ski', 'skies': 'sky', 'dying': 'die', |
||
779 | 'lying': 'lie', 'tying': 'tie', |
||
780 | # special -LY cases: |
||
781 | 'idly': 'idl', 'gently': 'gentl', 'ugly': 'ugli', |
||
782 | 'early': 'earli', 'only': 'onli', 'singly': 'singl'} |
||
783 | _exception1set = {'sky', 'news', 'howe', 'atlas', 'cosmos', 'bias', |
||
784 | 'andes'} |
||
785 | _exception2set = {'inning', 'outing', 'canning', 'herring', 'earring', |
||
786 | 'proceed', 'exceed', 'succeed'} |
||
787 | |||
788 | # lowercase, normalize, and compose |
||
789 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
790 | # replace apostrophe-like characters with U+0027, per |
||
791 | # http://snowball.tartarus.org/texts/apostrophe.html |
||
792 | word = word.replace('’', '\'') |
||
793 | word = word.replace('’', '\'') |
||
794 | |||
795 | # Exceptions 1 |
||
796 | if word in _exception1dict: |
||
797 | return _exception1dict[word] |
||
798 | elif word in _exception1set: |
||
799 | return word |
||
800 | |||
801 | # Return word if stem is shorter than 3 |
||
802 | if len(word) < 3: |
||
803 | return word |
||
804 | |||
805 | # Remove initial ', if present. |
||
806 | while word and word[0] == '\'': |
||
807 | word = word[1:] |
||
808 | # Return word if stem is shorter than 2 |
||
809 | if len(word) < 2: |
||
810 | return word |
||
811 | |||
812 | # Re-map vocalic Y to y (Y will be C, y will be V) |
||
813 | if word[0] == 'y': |
||
814 | word = 'Y' + word[1:] |
||
815 | for i in range(1, len(word)): |
||
816 | if word[i] == 'y' and word[i-1] in _vowels: |
||
817 | word = word[:i] + 'Y' + word[i+1:] |
||
818 | |||
819 | r1_start = _sb_r1(word, _vowels, _r1_prefixes) |
||
820 | r2_start = _sb_r2(word, _vowels, _r1_prefixes) |
||
821 | |||
822 | # Step 0 |
||
823 | if word[-3:] == '\'s\'': |
||
824 | word = word[:-3] |
||
825 | elif word[-2:] == '\'s': |
||
826 | word = word[:-2] |
||
827 | elif word[-1:] == '\'': |
||
828 | word = word[:-1] |
||
829 | # Return word if stem is shorter than 2 |
||
830 | if len(word) < 3: |
||
831 | return word |
||
832 | |||
833 | # Step 1a |
||
834 | if word[-4:] == 'sses': |
||
835 | word = word[:-2] |
||
836 | elif word[-3:] in {'ied', 'ies'}: |
||
837 | if len(word) > 4: |
||
838 | word = word[:-2] |
||
839 | else: |
||
840 | word = word[:-1] |
||
841 | elif word[-2:] in {'us', 'ss'}: |
||
842 | pass |
||
843 | elif word[-1] == 's': |
||
844 | if _sb_has_vowel(word[:-2], _vowels): |
||
845 | word = word[:-1] |
||
846 | |||
847 | # Exceptions 2 |
||
848 | if word in _exception2set: |
||
849 | return word |
||
850 | |||
851 | # Step 1b |
||
852 | step1b_flag = False |
||
853 | if word[-5:] == 'eedly': |
||
854 | if len(word[r1_start:]) >= 5: |
||
855 | word = word[:-3] |
||
856 | elif word[-5:] == 'ingly': |
||
857 | if _sb_has_vowel(word[:-5], _vowels): |
||
858 | word = word[:-5] |
||
859 | step1b_flag = True |
||
860 | elif word[-4:] == 'edly': |
||
861 | if _sb_has_vowel(word[:-4], _vowels): |
||
862 | word = word[:-4] |
||
863 | step1b_flag = True |
||
864 | elif word[-3:] == 'eed': |
||
865 | if len(word[r1_start:]) >= 3: |
||
866 | word = word[:-1] |
||
867 | elif word[-3:] == 'ing': |
||
868 | if _sb_has_vowel(word[:-3], _vowels): |
||
869 | word = word[:-3] |
||
870 | step1b_flag = True |
||
871 | elif word[-2:] == 'ed': |
||
872 | if _sb_has_vowel(word[:-2], _vowels): |
||
873 | word = word[:-2] |
||
874 | step1b_flag = True |
||
875 | elif early_english: |
||
876 | if word[-3:] == 'est': |
||
877 | if _sb_has_vowel(word[:-3], _vowels): |
||
878 | word = word[:-3] |
||
879 | step1b_flag = True |
||
880 | elif word[-3:] == 'eth': |
||
881 | if _sb_has_vowel(word[:-3], _vowels): |
||
882 | word = word[:-3] |
||
883 | step1b_flag = True |
||
884 | |||
885 | if step1b_flag: |
||
886 | if word[-2:] in {'at', 'bl', 'iz'}: |
||
887 | word += 'e' |
||
888 | elif word[-2:] in _doubles: |
||
889 | word = word[:-1] |
||
890 | elif _sb_short_word(word, _vowels, _codanonvowels, _r1_prefixes): |
||
891 | word += 'e' |
||
892 | |||
893 | # Step 1c |
||
894 | if ((len(word) > 2 and word[-1] in {'Y', 'y'} and |
||
895 | word[-2] not in _vowels)): |
||
896 | word = word[:-1] + 'i' |
||
897 | |||
898 | # Step 2 |
||
899 | if word[-2] == 'a': |
||
900 | if word[-7:] == 'ational': |
||
901 | if len(word[r1_start:]) >= 7: |
||
902 | word = word[:-5] + 'e' |
||
903 | elif word[-6:] == 'tional': |
||
904 | if len(word[r1_start:]) >= 6: |
||
905 | word = word[:-2] |
||
906 | elif word[-2] == 'c': |
||
907 | if word[-4:] in {'enci', 'anci'}: |
||
908 | if len(word[r1_start:]) >= 4: |
||
909 | word = word[:-1] + 'e' |
||
910 | elif word[-2] == 'e': |
||
911 | if word[-4:] == 'izer': |
||
912 | if len(word[r1_start:]) >= 4: |
||
913 | word = word[:-1] |
||
914 | elif word[-2] == 'g': |
||
915 | if word[-3:] == 'ogi': |
||
916 | if ((r1_start >= 1 and len(word[r1_start:]) >= 3 and |
||
917 | word[-4] == 'l')): |
||
918 | word = word[:-1] |
||
919 | elif word[-2] == 'l': |
||
920 | if word[-6:] == 'lessli': |
||
921 | if len(word[r1_start:]) >= 6: |
||
922 | word = word[:-2] |
||
923 | elif word[-5:] in {'entli', 'fulli', 'ousli'}: |
||
924 | if len(word[r1_start:]) >= 5: |
||
925 | word = word[:-2] |
||
926 | elif word[-4:] == 'abli': |
||
927 | if len(word[r1_start:]) >= 4: |
||
928 | word = word[:-1] + 'e' |
||
929 | elif word[-4:] == 'alli': |
||
930 | if len(word[r1_start:]) >= 4: |
||
931 | word = word[:-2] |
||
932 | elif word[-3:] == 'bli': |
||
933 | if len(word[r1_start:]) >= 3: |
||
934 | word = word[:-1] + 'e' |
||
935 | elif word[-2:] == 'li': |
||
936 | if ((r1_start >= 1 and len(word[r1_start:]) >= 2 and |
||
937 | word[-3] in _li)): |
||
938 | word = word[:-2] |
||
939 | elif word[-2] == 'o': |
||
940 | if word[-7:] == 'ization': |
||
941 | if len(word[r1_start:]) >= 7: |
||
942 | word = word[:-5] + 'e' |
||
943 | elif word[-5:] == 'ation': |
||
944 | if len(word[r1_start:]) >= 5: |
||
945 | word = word[:-3] + 'e' |
||
946 | elif word[-4:] == 'ator': |
||
947 | if len(word[r1_start:]) >= 4: |
||
948 | word = word[:-2] + 'e' |
||
949 | elif word[-2] == 's': |
||
950 | if word[-7:] in {'fulness', 'ousness', 'iveness'}: |
||
951 | if len(word[r1_start:]) >= 7: |
||
952 | word = word[:-4] |
||
953 | elif word[-5:] == 'alism': |
||
954 | if len(word[r1_start:]) >= 5: |
||
955 | word = word[:-3] |
||
956 | elif word[-2] == 't': |
||
957 | if word[-6:] == 'biliti': |
||
958 | if len(word[r1_start:]) >= 6: |
||
959 | word = word[:-5] + 'le' |
||
960 | elif word[-5:] == 'aliti': |
||
961 | if len(word[r1_start:]) >= 5: |
||
962 | word = word[:-3] |
||
963 | elif word[-5:] == 'iviti': |
||
964 | if len(word[r1_start:]) >= 5: |
||
965 | word = word[:-3] + 'e' |
||
966 | |||
967 | # Step 3 |
||
968 | if word[-7:] == 'ational': |
||
969 | if len(word[r1_start:]) >= 7: |
||
970 | word = word[:-5] + 'e' |
||
971 | elif word[-6:] == 'tional': |
||
972 | if len(word[r1_start:]) >= 6: |
||
973 | word = word[:-2] |
||
974 | elif word[-5:] in {'alize', 'icate', 'iciti'}: |
||
975 | if len(word[r1_start:]) >= 5: |
||
976 | word = word[:-3] |
||
977 | elif word[-5:] == 'ative': |
||
978 | if len(word[r2_start:]) >= 5: |
||
979 | word = word[:-5] |
||
980 | elif word[-4:] == 'ical': |
||
981 | if len(word[r1_start:]) >= 4: |
||
982 | word = word[:-2] |
||
983 | elif word[-4:] == 'ness': |
||
984 | if len(word[r1_start:]) >= 4: |
||
985 | word = word[:-4] |
||
986 | elif word[-3:] == 'ful': |
||
987 | if len(word[r1_start:]) >= 3: |
||
988 | word = word[:-3] |
||
989 | |||
990 | # Step 4 |
||
991 | for suffix in ('ement', 'ance', 'ence', 'able', 'ible', 'ment', 'ant', |
||
992 | 'ent', 'ism', 'ate', 'iti', 'ous', 'ive', 'ize', 'al', 'er', |
||
993 | 'ic'): |
||
994 | if word[-len(suffix):] == suffix: |
||
995 | if len(word[r2_start:]) >= len(suffix): |
||
996 | word = word[:-len(suffix)] |
||
997 | break |
||
998 | else: |
||
999 | if word[-3:] == 'ion': |
||
1000 | if ((len(word[r2_start:]) >= 3 and len(word) >= 4 and |
||
1001 | word[-4] in tuple('st'))): |
||
1002 | word = word[:-3] |
||
1003 | |||
1004 | # Step 5 |
||
1005 | if word[-1] == 'e': |
||
1006 | if (len(word[r2_start:]) >= 1 or |
||
1007 | (len(word[r1_start:]) >= 1 and |
||
1008 | not _sb_ends_in_short_syllable(word[:-1], _vowels, |
||
1009 | _codanonvowels))): |
||
1010 | word = word[:-1] |
||
1011 | elif word[-1] == 'l': |
||
1012 | if len(word[r2_start:]) >= 1 and word[-2] == 'l': |
||
1013 | word = word[:-1] |
||
1014 | |||
1015 | # Change 'Y' back to 'y' if it survived stemming |
||
1016 | for i in range(0, len(word)): |
||
1017 | if word[i] == 'Y': |
||
1018 | word = word[:i] + 'y' + word[i+1:] |
||
1019 | |||
1020 | return word |
||
1021 | |||
1022 | |||
1023 | def sb_german(word, alternate_vowels=False): |
||
1024 | """Return Snowball German stem. |
||
1025 | |||
1026 | The Snowball German stemmer is defined at: |
||
1027 | http://snowball.tartarus.org/algorithms/german/stemmer.html |
||
1028 | |||
1029 | :param word: the word to calculate the stem of |
||
1030 | :param alternate_vowels: composes ae as ä, oe as ö, and ue as ü before |
||
1031 | running the algorithm |
||
1032 | :returns: word stem |
||
1033 | :rtype: str |
||
1034 | |||
1035 | >>> sb_german('lesen') |
||
1036 | 'les' |
||
1037 | >>> sb_german('graues') |
||
1038 | 'grau' |
||
1039 | >>> sb_german('buchstabieren') |
||
1040 | 'buchstabi' |
||
1041 | """ |
||
1042 | # pylint: disable=too-many-branches |
||
1043 | |||
1044 | _vowels = {'a', 'e', 'i', 'o', 'u', 'y', 'ä', 'ö', 'ü'} |
||
1045 | _s_endings = {'b', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 'n', 'r', 't'} |
||
1046 | _st_endings = {'b', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 'n', 't'} |
||
1047 | |||
1048 | # lowercase, normalize, and compose |
||
1049 | word = unicodedata.normalize('NFC', word.lower()) |
||
1050 | word = word.replace('ß', 'ss') |
||
1051 | |||
1052 | if len(word) > 2: |
||
1053 | for i in range(2, len(word)): |
||
1054 | if word[i] in _vowels and word[i-2] in _vowels: |
||
1055 | if word[i-1] == 'u': |
||
1056 | word = word[:i-1] + 'U' + word[i:] |
||
1057 | elif word[i-1] == 'y': |
||
1058 | word = word[:i-1] + 'Y' + word[i:] |
||
1059 | |||
1060 | if alternate_vowels: |
||
1061 | word = word.replace('ae', 'ä') |
||
1062 | word = word.replace('oe', 'ö') |
||
1063 | word = word.replace('que', 'Q') |
||
1064 | word = word.replace('ue', 'ü') |
||
1065 | word = word.replace('Q', 'que') |
||
1066 | |||
1067 | r1_start = max(3, _sb_r1(word, _vowels)) |
||
1068 | r2_start = _sb_r2(word, _vowels) |
||
1069 | |||
1070 | # Step 1 |
||
1071 | niss_flag = False |
||
1072 | if word[-3:] == 'ern': |
||
1073 | if len(word[r1_start:]) >= 3: |
||
1074 | word = word[:-3] |
||
1075 | elif word[-2:] == 'em': |
||
1076 | if len(word[r1_start:]) >= 2: |
||
1077 | word = word[:-2] |
||
1078 | elif word[-2:] == 'er': |
||
1079 | if len(word[r1_start:]) >= 2: |
||
1080 | word = word[:-2] |
||
1081 | elif word[-2:] == 'en': |
||
1082 | if len(word[r1_start:]) >= 2: |
||
1083 | word = word[:-2] |
||
1084 | niss_flag = True |
||
1085 | elif word[-2:] == 'es': |
||
1086 | if len(word[r1_start:]) >= 2: |
||
1087 | word = word[:-2] |
||
1088 | niss_flag = True |
||
1089 | elif word[-1:] == 'e': |
||
1090 | if len(word[r1_start:]) >= 1: |
||
1091 | word = word[:-1] |
||
1092 | niss_flag = True |
||
1093 | elif word[-1:] == 's': |
||
1094 | if ((len(word[r1_start:]) >= 1 and len(word) >= 2 and |
||
1095 | word[-2] in _s_endings)): |
||
1096 | word = word[:-1] |
||
1097 | |||
1098 | if niss_flag and word[-4:] == 'niss': |
||
1099 | word = word[:-1] |
||
1100 | |||
1101 | # Step 2 |
||
1102 | if word[-3:] == 'est': |
||
1103 | if len(word[r1_start:]) >= 3: |
||
1104 | word = word[:-3] |
||
1105 | elif word[-2:] == 'en': |
||
1106 | if len(word[r1_start:]) >= 2: |
||
1107 | word = word[:-2] |
||
1108 | elif word[-2:] == 'er': |
||
1109 | if len(word[r1_start:]) >= 2: |
||
1110 | word = word[:-2] |
||
1111 | elif word[-2:] == 'st': |
||
1112 | if ((len(word[r1_start:]) >= 2 and len(word) >= 6 and |
||
1113 | word[-3] in _st_endings)): |
||
1114 | word = word[:-2] |
||
1115 | |||
1116 | # Step 3 |
||
1117 | if word[-4:] == 'isch': |
||
1118 | if len(word[r2_start:]) >= 4 and word[-5] != 'e': |
||
1119 | word = word[:-4] |
||
1120 | elif word[-4:] in {'lich', 'heit'}: |
||
1121 | if len(word[r2_start:]) >= 4: |
||
1122 | word = word[:-4] |
||
1123 | if ((word[-2:] in {'er', 'en'} and |
||
1124 | len(word[r1_start:]) >= 2)): |
||
1125 | word = word[:-2] |
||
1126 | elif word[-4:] == 'keit': |
||
1127 | if len(word[r2_start:]) >= 4: |
||
1128 | word = word[:-4] |
||
1129 | if word[-4:] == 'lich' and len(word[r2_start:]) >= 4: |
||
1130 | word = word[:-4] |
||
1131 | elif word[-2:] == 'ig' and len(word[r2_start:]) >= 2: |
||
1132 | word = word[:-2] |
||
1133 | elif word[-3:] in {'end', 'ung'}: |
||
1134 | if len(word[r2_start:]) >= 3: |
||
1135 | word = word[:-3] |
||
1136 | if ((word[-2:] == 'ig' and len(word[r2_start:]) >= 2 and |
||
1137 | word[-3] != 'e')): |
||
1138 | word = word[:-2] |
||
1139 | elif word[-2:] in {'ig', 'ik'}: |
||
1140 | if len(word[r2_start:]) >= 2 and word[-3] != 'e': |
||
1141 | word = word[:-2] |
||
1142 | |||
1143 | # Change 'Y' and 'U' back to lowercase if survived stemming |
||
1144 | for i in range(0, len(word)): |
||
1145 | if word[i] == 'Y': |
||
1146 | word = word[:i] + 'y' + word[i+1:] |
||
1147 | elif word[i] == 'U': |
||
1148 | word = word[:i] + 'u' + word[i+1:] |
||
1149 | |||
1150 | # Remove umlauts |
||
1151 | _umlauts = dict(zip((ord(_) for _ in 'äöü'), 'aou')) |
||
1152 | word = word.translate(_umlauts) |
||
1153 | |||
1154 | return word |
||
1155 | |||
1156 | |||
1157 | def sb_dutch(word): |
||
1158 | """Return Snowball Dutch stem. |
||
1159 | |||
1160 | The Snowball Dutch stemmer is defined at: |
||
1161 | http://snowball.tartarus.org/algorithms/dutch/stemmer.html |
||
1162 | |||
1163 | :param word: the word to calculate the stem of |
||
1164 | :returns: word stem |
||
1165 | :rtype: str |
||
1166 | |||
1167 | >>> sb_dutch('lezen') |
||
1168 | 'lez' |
||
1169 | >>> sb_dutch('opschorting') |
||
1170 | 'opschort' |
||
1171 | >>> sb_dutch('ongrijpbaarheid') |
||
1172 | 'ongrijp' |
||
1173 | """ |
||
1174 | # pylint: disable=too-many-branches |
||
1175 | |||
1176 | _vowels = {'a', 'e', 'i', 'o', 'u', 'y', 'è'} |
||
1177 | _not_s_endings = {'a', 'e', 'i', 'j', 'o', 'u', 'y', 'è'} |
||
1178 | |||
1179 | def _undouble(word): |
||
1180 | """Undouble endings -kk, -dd, and -tt.""" |
||
1181 | if ((len(word) > 1 and word[-1] == word[-2] and |
||
1182 | word[-1] in {'d', 'k', 't'})): |
||
1183 | return word[:-1] |
||
1184 | return word |
||
1185 | |||
1186 | # lowercase, normalize, decompose, filter umlauts & acutes out, and compose |
||
1187 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
1188 | _accented = dict(zip((ord(_) for _ in 'äëïöüáéíóú'), 'aeiouaeiou')) |
||
1189 | word = word.translate(_accented) |
||
1190 | |||
1191 | for i in range(len(word)): |
||
1192 | if i == 0 and word[0] == 'y': |
||
1193 | word = 'Y' + word[1:] |
||
1194 | elif word[i] == 'y' and word[i-1] in _vowels: |
||
1195 | word = word[:i] + 'Y' + word[i+1:] |
||
1196 | elif (word[i] == 'i' and word[i-1] in _vowels and i+1 < len(word) and |
||
1197 | word[i+1] in _vowels): |
||
1198 | word = word[:i] + 'I' + word[i+1:] |
||
1199 | |||
1200 | r1_start = max(3, _sb_r1(word, _vowels)) |
||
1201 | r2_start = _sb_r2(word, _vowels) |
||
1202 | |||
1203 | # Step 1 |
||
1204 | if word[-5:] == 'heden': |
||
1205 | if len(word[r1_start:]) >= 5: |
||
1206 | word = word[:-3] + 'id' |
||
1207 | elif word[-3:] == 'ene': |
||
1208 | if ((len(word[r1_start:]) >= 3 and |
||
1209 | (word[-4] not in _vowels and word[-6:-3] != 'gem'))): |
||
1210 | word = _undouble(word[:-3]) |
||
1211 | elif word[-2:] == 'en': |
||
1212 | if ((len(word[r1_start:]) >= 2 and |
||
1213 | (word[-3] not in _vowels and word[-5:-2] != 'gem'))): |
||
1214 | word = _undouble(word[:-2]) |
||
1215 | elif word[-2:] == 'se': |
||
1216 | if len(word[r1_start:]) >= 2 and word[-3] not in _not_s_endings: |
||
1217 | word = word[:-2] |
||
1218 | elif word[-1:] == 's': |
||
1219 | if len(word[r1_start:]) >= 1 and word[-2] not in _not_s_endings: |
||
1220 | word = word[:-1] |
||
1221 | |||
1222 | # Step 2 |
||
1223 | e_removed = False |
||
1224 | if word[-1:] == 'e': |
||
1225 | if len(word[r1_start:]) >= 1 and word[-2] not in _vowels: |
||
1226 | word = _undouble(word[:-1]) |
||
1227 | e_removed = True |
||
1228 | |||
1229 | # Step 3a |
||
1230 | if word[-4:] == 'heid': |
||
1231 | if len(word[r2_start:]) >= 4 and word[-5] != 'c': |
||
1232 | word = word[:-4] |
||
1233 | if word[-2:] == 'en': |
||
1234 | if ((len(word[r1_start:]) >= 2 and |
||
1235 | (word[-3] not in _vowels and word[-5:-2] != 'gem'))): |
||
1236 | word = _undouble(word[:-2]) |
||
1237 | |||
1238 | # Step 3b |
||
1239 | if word[-4:] == 'lijk': |
||
1240 | if len(word[r2_start:]) >= 4: |
||
1241 | word = word[:-4] |
||
1242 | # Repeat step 2 |
||
1243 | if word[-1:] == 'e': |
||
1244 | if len(word[r1_start:]) >= 1 and word[-2] not in _vowels: |
||
1245 | word = _undouble(word[:-1]) |
||
1246 | elif word[-4:] == 'baar': |
||
1247 | if len(word[r2_start:]) >= 4: |
||
1248 | word = word[:-4] |
||
1249 | elif word[-3:] in ('end', 'ing'): |
||
1250 | if len(word[r2_start:]) >= 3: |
||
1251 | word = word[:-3] |
||
1252 | if ((word[-2:] == 'ig' and len(word[r2_start:]) >= 2 and |
||
1253 | word[-3] != 'e')): |
||
1254 | word = word[:-2] |
||
1255 | else: |
||
1256 | word = _undouble(word) |
||
1257 | elif word[-3:] == 'bar': |
||
1258 | if len(word[r2_start:]) >= 3 and e_removed: |
||
1259 | word = word[:-3] |
||
1260 | elif word[-2:] == 'ig': |
||
1261 | if len(word[r2_start:]) >= 2 and word[-3] != 'e': |
||
1262 | word = word[:-2] |
||
1263 | |||
1264 | # Step 4 |
||
1265 | if ((len(word) >= 4 and |
||
1266 | word[-3] == word[-2] and word[-2] in {'a', 'e', 'o', 'u'} and |
||
1267 | word[-4] not in _vowels and |
||
1268 | word[-1] not in _vowels and word[-1] != 'I')): |
||
1269 | word = word[:-2] + word[-1] |
||
1270 | |||
1271 | # Change 'Y' and 'U' back to lowercase if survived stemming |
||
1272 | for i in range(0, len(word)): |
||
1273 | if word[i] == 'Y': |
||
1274 | word = word[:i] + 'y' + word[i+1:] |
||
1275 | elif word[i] == 'I': |
||
1276 | word = word[:i] + 'i' + word[i+1:] |
||
1277 | |||
1278 | return word |
||
1279 | |||
1280 | |||
1281 | def sb_norwegian(word): |
||
1282 | """Return Snowball Norwegian stem. |
||
1283 | |||
1284 | The Snowball Norwegian stemmer is defined at: |
||
1285 | http://snowball.tartarus.org/algorithms/norwegian/stemmer.html |
||
1286 | |||
1287 | :param word: the word to calculate the stem of |
||
1288 | :returns: word stem |
||
1289 | :rtype: str |
||
1290 | |||
1291 | >>> sb_norwegian('lese') |
||
1292 | 'les' |
||
1293 | >>> sb_norwegian('suspensjon') |
||
1294 | 'suspensjon' |
||
1295 | >>> sb_norwegian('sikkerhet') |
||
1296 | 'sikker' |
||
1297 | """ |
||
1298 | _vowels = {'a', 'e', 'i', 'o', 'u', 'y', 'å', 'æ', 'ø'} |
||
1299 | _s_endings = {'b', 'c', 'd', 'f', 'g', 'h', 'j', 'l', 'm', 'n', 'o', 'p', |
||
1300 | 'r', 't', 'v', 'y', 'z'} |
||
1301 | # lowercase, normalize, and compose |
||
1302 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
1303 | |||
1304 | r1_start = min(max(3, _sb_r1(word, _vowels)), len(word)) |
||
1305 | |||
1306 | # Step 1 |
||
1307 | _r1 = word[r1_start:] |
||
1308 | if _r1[-7:] == 'hetenes': |
||
1309 | word = word[:-7] |
||
1310 | elif _r1[-6:] in {'hetene', 'hetens'}: |
||
1311 | word = word[:-6] |
||
1312 | elif _r1[-5:] in {'heten', 'heter', 'endes'}: |
||
1313 | word = word[:-5] |
||
1314 | elif _r1[-4:] in {'ande', 'ende', 'edes', 'enes', 'erte'}: |
||
1315 | if word[-4:] == 'erte': |
||
1316 | word = word[:-2] |
||
1317 | else: |
||
1318 | word = word[:-4] |
||
1319 | elif _r1[-3:] in {'ede', 'ane', 'ene', 'ens', 'ers', 'ets', 'het', 'ast', |
||
1320 | 'ert'}: |
||
1321 | if word[-3:] == 'ert': |
||
1322 | word = word[:-1] |
||
1323 | else: |
||
1324 | word = word[:-3] |
||
1325 | elif _r1[-2:] in {'en', 'ar', 'er', 'as', 'es', 'et'}: |
||
1326 | word = word[:-2] |
||
1327 | elif _r1[-1:] in {'a', 'e'}: |
||
1328 | word = word[:-1] |
||
1329 | elif _r1[-1:] == 's': |
||
1330 | if (((len(word) > 1 and word[-2] in _s_endings) or |
||
1331 | (len(word) > 2 and word[-2] == 'k' and word[-3] not in _vowels))): |
||
1332 | word = word[:-1] |
||
1333 | |||
1334 | # Step 2 |
||
1335 | if word[r1_start:][-2:] in {'dt', 'vt'}: |
||
1336 | word = word[:-1] |
||
1337 | |||
1338 | # Step 3 |
||
1339 | _r1 = word[r1_start:] |
||
1340 | if _r1[-7:] == 'hetslov': |
||
1341 | word = word[:-7] |
||
1342 | elif _r1[-4:] in {'eleg', 'elig', 'elov', 'slov'}: |
||
1343 | word = word[:-4] |
||
1344 | elif _r1[-3:] in {'leg', 'eig', 'lig', 'els', 'lov'}: |
||
1345 | word = word[:-3] |
||
1346 | elif _r1[-2:] == 'ig': |
||
1347 | word = word[:-2] |
||
1348 | |||
1349 | return word |
||
1350 | |||
1351 | |||
1352 | def sb_swedish(word): |
||
1353 | """Return Snowball Swedish stem. |
||
1354 | |||
1355 | The Snowball Swedish stemmer is defined at: |
||
1356 | http://snowball.tartarus.org/algorithms/swedish/stemmer.html |
||
1357 | |||
1358 | :param word: the word to calculate the stem of |
||
1359 | :returns: word stem |
||
1360 | :rtype: str |
||
1361 | |||
1362 | >>> sb_swedish('undervisa') |
||
1363 | 'undervis' |
||
1364 | >>> sb_swedish('suspension') |
||
1365 | 'suspension' |
||
1366 | >>> sb_swedish('visshet') |
||
1367 | 'viss' |
||
1368 | """ |
||
1369 | _vowels = {'a', 'e', 'i', 'o', 'u', 'y', 'ä', 'å', 'ö'} |
||
1370 | _s_endings = {'b', 'c', 'd', 'f', 'g', 'h', 'j', 'k', 'l', 'm', 'n', |
||
1371 | 'o', 'p', 'r', 't', 'v', 'y'} |
||
1372 | |||
1373 | # lowercase, normalize, and compose |
||
1374 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
1375 | |||
1376 | r1_start = min(max(3, _sb_r1(word, _vowels)), len(word)) |
||
1377 | |||
1378 | # Step 1 |
||
1379 | _r1 = word[r1_start:] |
||
1380 | View Code Duplication | if _r1[-7:] == 'heterna': |
|
1381 | word = word[:-7] |
||
1382 | elif _r1[-6:] == 'hetens': |
||
1383 | word = word[:-6] |
||
1384 | elif _r1[-5:] in {'anden', 'heten', 'heter', 'arnas', 'ernas', 'ornas', |
||
1385 | 'andes', 'arens', 'andet'}: |
||
1386 | word = word[:-5] |
||
1387 | elif _r1[-4:] in {'arna', 'erna', 'orna', 'ande', 'arne', 'aste', 'aren', |
||
1388 | 'ades', 'erns'}: |
||
1389 | word = word[:-4] |
||
1390 | elif _r1[-3:] in {'ade', 'are', 'ern', 'ens', 'het', 'ast'}: |
||
1391 | word = word[:-3] |
||
1392 | elif _r1[-2:] in {'ad', 'en', 'ar', 'er', 'or', 'as', 'es', 'at'}: |
||
1393 | word = word[:-2] |
||
1394 | elif _r1[-1:] in {'a', 'e'}: |
||
1395 | word = word[:-1] |
||
1396 | elif _r1[-1:] == 's': |
||
1397 | if len(word) > 1 and word[-2] in _s_endings: |
||
1398 | word = word[:-1] |
||
1399 | |||
1400 | # Step 2 |
||
1401 | if word[r1_start:][-2:] in {'dd', 'gd', 'nn', 'dt', 'gt', 'kt', 'tt'}: |
||
1402 | word = word[:-1] |
||
1403 | |||
1404 | # Step 3 |
||
1405 | _r1 = word[r1_start:] |
||
1406 | if _r1[-5:] == 'fullt': |
||
1407 | word = word[:-1] |
||
1408 | elif _r1[-4:] == 'löst': |
||
1409 | word = word[:-1] |
||
1410 | elif _r1[-3:] in {'lig', 'els'}: |
||
1411 | word = word[:-3] |
||
1412 | elif _r1[-2:] == 'ig': |
||
1413 | word = word[:-2] |
||
1414 | |||
1415 | return word |
||
1416 | |||
1417 | |||
1418 | def sb_danish(word): |
||
1419 | """Return Snowball Danish stem. |
||
1420 | |||
1421 | The Snowball Danish stemmer is defined at: |
||
1422 | http://snowball.tartarus.org/algorithms/danish/stemmer.html |
||
1423 | |||
1424 | :param word: the word to calculate the stem of |
||
1425 | :returns: word stem |
||
1426 | :rtype: str |
||
1427 | |||
1428 | >>> sb_danish('underviser') |
||
1429 | 'undervis' |
||
1430 | >>> sb_danish('suspension') |
||
1431 | 'suspension' |
||
1432 | >>> sb_danish('sikkerhed') |
||
1433 | 'sikker' |
||
1434 | """ |
||
1435 | _vowels = {'a', 'e', 'i', 'o', 'u', 'y', 'å', 'æ', 'ø'} |
||
1436 | _s_endings = {'a', 'b', 'c', 'd', 'f', 'g', 'h', 'j', 'k', 'l', 'm', 'n', |
||
1437 | 'o', 'p', 'r', 't', 'v', 'y', 'z', 'å'} |
||
1438 | |||
1439 | # lowercase, normalize, and compose |
||
1440 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
1441 | |||
1442 | r1_start = min(max(3, _sb_r1(word, _vowels)), len(word)) |
||
1443 | |||
1444 | # Step 1 |
||
1445 | _r1 = word[r1_start:] |
||
1446 | View Code Duplication | if _r1[-7:] == 'erendes': |
|
1447 | word = word[:-7] |
||
1448 | elif _r1[-6:] in {'erende', 'hedens'}: |
||
1449 | word = word[:-6] |
||
1450 | elif _r1[-5:] in {'ethed', 'erede', 'heden', 'heder', 'endes', 'ernes', |
||
1451 | 'erens', 'erets'}: |
||
1452 | word = word[:-5] |
||
1453 | elif _r1[-4:] in {'ered', 'ende', 'erne', 'eren', 'erer', 'heds', 'enes', |
||
1454 | 'eres', 'eret'}: |
||
1455 | word = word[:-4] |
||
1456 | elif _r1[-3:] in {'hed', 'ene', 'ere', 'ens', 'ers', 'ets'}: |
||
1457 | word = word[:-3] |
||
1458 | elif _r1[-2:] in {'en', 'er', 'es', 'et'}: |
||
1459 | word = word[:-2] |
||
1460 | elif _r1[-1:] == 'e': |
||
1461 | word = word[:-1] |
||
1462 | elif _r1[-1:] == 's': |
||
1463 | if len(word) > 1 and word[-2] in _s_endings: |
||
1464 | word = word[:-1] |
||
1465 | |||
1466 | # Step 2 |
||
1467 | if word[r1_start:][-2:] in {'gd', 'dt', 'gt', 'kt'}: |
||
1468 | word = word[:-1] |
||
1469 | |||
1470 | # Step 3 |
||
1471 | if word[-4:] == 'igst': |
||
1472 | word = word[:-2] |
||
1473 | |||
1474 | _r1 = word[r1_start:] |
||
1475 | repeat_step2 = False |
||
1476 | if _r1[-4:] == 'elig': |
||
1477 | word = word[:-4] |
||
1478 | repeat_step2 = True |
||
1479 | elif _r1[-4:] == 'løst': |
||
1480 | word = word[:-1] |
||
1481 | elif _r1[-3:] in {'lig', 'els'}: |
||
1482 | word = word[:-3] |
||
1483 | repeat_step2 = True |
||
1484 | elif _r1[-2:] == 'ig': |
||
1485 | word = word[:-2] |
||
1486 | repeat_step2 = True |
||
1487 | |||
1488 | if repeat_step2: |
||
1489 | if word[r1_start:][-2:] in {'gd', 'dt', 'gt', 'kt'}: |
||
1490 | word = word[:-1] |
||
1491 | |||
1492 | # Step 4 |
||
1493 | if ((len(word[r1_start:]) >= 1 and len(word) >= 2 and |
||
1494 | word[-1] == word[-2] and word[-1] not in _vowels)): |
||
1495 | word = word[:-1] |
||
1496 | |||
1497 | return word |
||
1498 | |||
1499 | |||
1500 | def clef_german(word): |
||
1501 | """Return CLEF German stem. |
||
1502 | |||
1503 | The CLEF German stemmer is defined at: |
||
1504 | http://members.unine.ch/jacques.savoy/clef/germanStemmer.txt |
||
1505 | |||
1506 | :param word: the word to calculate the stem of |
||
1507 | :returns: word stem |
||
1508 | :rtype: str |
||
1509 | |||
1510 | >>> clef_german('lesen') |
||
1511 | 'lese' |
||
1512 | >>> clef_german('graues') |
||
1513 | 'grau' |
||
1514 | >>> clef_german('buchstabieren') |
||
1515 | 'buchstabier' |
||
1516 | """ |
||
1517 | # lowercase, normalize, and compose |
||
1518 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
1519 | |||
1520 | # remove umlauts |
||
1521 | _umlauts = dict(zip((ord(_) for _ in 'äöü'), 'aou')) |
||
1522 | word = word.translate(_umlauts) |
||
1523 | |||
1524 | # remove plurals |
||
1525 | wlen = len(word)-1 |
||
1526 | |||
1527 | if wlen > 3: |
||
1528 | if wlen > 5: |
||
1529 | if word[-3:] == 'nen': |
||
1530 | return word[:-3] |
||
1531 | if wlen > 4: |
||
1532 | if word[-2:] in {'en', 'se', 'es', 'er'}: |
||
1533 | return word[:-2] |
||
1534 | if word[-1] in {'e', 'n', 'r', 's'}: |
||
1535 | return word[:-1] |
||
1536 | return word |
||
1537 | |||
1538 | |||
1539 | def clef_german_plus(word): |
||
1540 | """Return 'CLEF German stemmer plus' stem. |
||
1541 | |||
1542 | The CLEF German stemmer plus is defined at: |
||
1543 | http://members.unine.ch/jacques.savoy/clef/germanStemmerPlus.txt |
||
1544 | |||
1545 | :param word: the word to calculate the stem of |
||
1546 | :returns: word stem |
||
1547 | :rtype: str |
||
1548 | |||
1549 | >>> clef_german_plus('lesen') |
||
1550 | 'les' |
||
1551 | >>> clef_german_plus('graues') |
||
1552 | 'grau' |
||
1553 | >>> clef_german_plus('buchstabieren') |
||
1554 | 'buchstabi' |
||
1555 | """ |
||
1556 | _st_ending = {'b', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 'n', 't'} |
||
1557 | |||
1558 | # lowercase, normalize, and compose |
||
1559 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
1560 | |||
1561 | # remove umlauts |
||
1562 | _accents = dict(zip((ord(_) for _ in 'äàáâöòóôïìíîüùúû'), |
||
1563 | 'aaaaooooiiiiuuuu')) |
||
1564 | word = word.translate(_accents) |
||
1565 | |||
1566 | # Step 1 |
||
1567 | wlen = len(word)-1 |
||
1568 | if wlen > 4 and word[-3:] == 'ern': |
||
1569 | word = word[:-3] |
||
1570 | elif wlen > 3 and word[-2:] in {'em', 'en', 'er', 'es'}: |
||
1571 | word = word[:-2] |
||
1572 | elif wlen > 2 and (word[-1] == 'e' or |
||
1573 | (word[-1] == 's' and word[-2] in _st_ending)): |
||
1574 | word = word[:-1] |
||
1575 | |||
1576 | # Step 2 |
||
1577 | wlen = len(word)-1 |
||
1578 | if wlen > 4 and word[-3:] == 'est': |
||
1579 | word = word[:-3] |
||
1580 | elif wlen > 3 and (word[-2:] in {'er', 'en'} or |
||
1581 | (word[-2:] == 'st' and word[-3] in _st_ending)): |
||
1582 | word = word[:-2] |
||
1583 | |||
1584 | return word |
||
1585 | |||
1586 | |||
1587 | def clef_swedish(word): |
||
1588 | """Return CLEF Swedish stem. |
||
1589 | |||
1590 | The CLEF Swedish stemmer is defined at: |
||
1591 | http://members.unine.ch/jacques.savoy/clef/swedishStemmer.txt |
||
1592 | |||
1593 | :param word: the word to calculate the stem of |
||
1594 | :returns: word stem |
||
1595 | :rtype: str |
||
1596 | |||
1597 | >>> clef_swedish('undervisa') |
||
1598 | 'undervis' |
||
1599 | >>> clef_swedish('suspension') |
||
1600 | 'suspensio' |
||
1601 | >>> clef_swedish('visshet') |
||
1602 | 'viss' |
||
1603 | """ |
||
1604 | wlen = len(word)-1 |
||
1605 | |||
1606 | if wlen > 3 and word[-1] == 's': |
||
1607 | word = word[:-1] |
||
1608 | wlen -= 1 |
||
1609 | |||
1610 | if wlen > 6: |
||
1611 | if word[-5:] in {'elser', 'heten'}: |
||
1612 | return word[:-5] |
||
1613 | if wlen > 5: |
||
1614 | if word[-4:] in {'arne', 'erna', 'ande', 'else', 'aste', 'orna', |
||
1615 | 'aren'}: |
||
1616 | return word[:-4] |
||
1617 | if wlen > 4: |
||
1618 | if word[-3:] in {'are', 'ast', 'het'}: |
||
1619 | return word[:-3] |
||
1620 | if wlen > 3: |
||
1621 | if word[-2:] in {'ar', 'er', 'or', 'en', 'at', 'te', 'et'}: |
||
1622 | return word[:-2] |
||
1623 | if wlen > 2: |
||
1624 | if word[-1] in {'a', 'e', 'n', 't'}: |
||
1625 | return word[:-1] |
||
1626 | return word |
||
1627 | |||
1628 | |||
1629 | def caumanns(word): |
||
1630 | """Return Caumanns German stem. |
||
1631 | |||
1632 | Jörg Caumanns' stemmer is described in his article at: |
||
1633 | http://edocs.fu-berlin.de/docs/servlets/MCRFileNodeServlet/FUDOCS_derivate_000000000350/tr-b-99-16.pdf |
||
1634 | |||
1635 | This implementation is based on the GermanStemFilter described at: |
||
1636 | http://www.evelix.ch/unternehmen/Blog/evelix/2013/11/11/inner-workings-of-the-german-analyzer-in-lucene |
||
1637 | |||
1638 | :param word: the word to calculate the stem of |
||
1639 | :returns: word stem |
||
1640 | :rtype: str |
||
1641 | |||
1642 | >>> caumanns('lesen') |
||
1643 | 'les' |
||
1644 | >>> caumanns('graues') |
||
1645 | 'grau' |
||
1646 | >>> caumanns('buchstabieren') |
||
1647 | 'buchstabier' |
||
1648 | """ |
||
1649 | if not word: |
||
1650 | return '' |
||
1651 | |||
1652 | upper_initial = word[0].isupper() |
||
1653 | word = unicodedata.normalize('NFC', text_type(word.lower())) |
||
1654 | |||
1655 | # # Part 2: Substitution |
||
1656 | # 1. Change umlauts to corresponding vowels & ß to ss |
||
1657 | _umlauts = dict(zip((ord(_) for _ in 'äöü'), 'aou')) |
||
1658 | word = word.translate(_umlauts) |
||
1659 | word = word.replace('ß', 'ss') |
||
1660 | |||
1661 | # 2. Change second of doubled characters to * |
||
1662 | newword = word[0] |
||
1663 | for i in range(1, len(word)): |
||
1664 | if newword[i-1] == word[i]: |
||
1665 | newword += '*' |
||
1666 | else: |
||
1667 | newword += word[i] |
||
1668 | word = newword |
||
1669 | |||
1670 | # 3. Replace sch, ch, ei, ie with $, §, %, & |
||
1671 | word = word.replace('sch', '$') |
||
1672 | word = word.replace('ch', '§') |
||
1673 | word = word.replace('ei', '%') |
||
1674 | word = word.replace('ie', '&') |
||
1675 | word = word.replace('ig', '#') |
||
1676 | word = word.replace('st', '!') |
||
1677 | |||
1678 | # # Part 1: Recursive Context-Free Stripping |
||
1679 | # 1. Remove the following 7 suffixes recursively |
||
1680 | while len(word) > 3: |
||
1681 | if (((len(word) > 4 and word[-2:] in {'em', 'er'}) or |
||
1682 | (len(word) > 5 and word[-2:] == 'nd'))): |
||
1683 | word = word[:-2] |
||
1684 | elif ((word[-1] in {'e', 's', 'n'}) or |
||
1685 | (not upper_initial and word[-1] in {'t', '!'})): |
||
1686 | word = word[:-1] |
||
1687 | else: |
||
1688 | break |
||
1689 | |||
1690 | # Additional optimizations: |
||
1691 | if len(word) > 5 and word[-5:] == 'erin*': |
||
1692 | word = word[:-1] |
||
1693 | if word[-1] == 'z': |
||
1694 | word = word[:-1] + 'x' |
||
1695 | |||
1696 | # Reverse substitutions: |
||
1697 | word = word.replace('$', 'sch') |
||
1698 | word = word.replace('§', 'ch') |
||
1699 | word = word.replace('%', 'ei') |
||
1700 | word = word.replace('&', 'ie') |
||
1701 | word = word.replace('#', 'ig') |
||
1702 | word = word.replace('!', 'st') |
||
1703 | |||
1704 | # Expand doubled |
||
1705 | word = ''.join([word[0]] + [word[i-1] if word[i] == '*' else word[i] for |
||
1706 | i in range(1, len(word))]) |
||
1707 | |||
1708 | # Finally, convert gege to ge |
||
1709 | if len(word) > 4: |
||
1710 | word = word.replace('gege', 'ge', 1) |
||
1711 | |||
1712 | return word |
||
1713 | |||
1714 | |||
1715 | def uealite(word, max_word_length=20, max_acro_length=8, return_rule_no=False, |
||
1716 | var=None): |
||
1717 | """Return UEA-Lite stem. |
||
1718 | |||
1719 | The UEA-Lite stemmer is discussed in: |
||
1720 | Jenkins, Marie-Claire and Dan Smith. 2005. "Conservative stemming for |
||
1721 | search and indexing." |
||
1722 | http://lemur.cmp.uea.ac.uk/Research/stemmer/stemmer25feb.pdf |
||
1723 | |||
1724 | This is chiefly based on the Java implementation of the algorithm, with |
||
1725 | variants based on the Perl implementation and Jason Adams' Ruby port. |
||
1726 | |||
1727 | Java version: http://lemur.cmp.uea.ac.uk/Research/stemmer/UEAstem.java |
||
1728 | Perl version: http://lemur.cmp.uea.ac.uk/Research/stemmer/UEAstem.pl |
||
1729 | Ruby version: https://github.com/ealdent/uea-stemmer |
||
1730 | |||
1731 | :param word: the word to calculate the stem of |
||
1732 | :param max_word_length: the maximum word length allowed |
||
1733 | :param return_rule_no: if True, returns the stem along with rule number |
||
1734 | :param var: variant to use (set to 'Adams' to use Jason Adams' rules, |
||
1735 | or 'Perl' to use the original Perl set of rules) |
||
1736 | :returns: word stem |
||
1737 | :rtype: str or tuple(str, int) |
||
1738 | """ |
||
1739 | problem_words = {'is', 'as', 'this', 'has', 'was', 'during'} |
||
1740 | |||
1741 | # rule table format: |
||
1742 | # top-level dictionary: length-of-suffix: dict-of-rules |
||
1743 | # dict-of-rules: suffix: (rule_no, suffix_length_to_delete, |
||
1744 | # suffix_to_append) |
||
1745 | rule_table = {7: {'titudes': (30, 1, None), |
||
1746 | 'fulness': (34, 4, None), |
||
1747 | 'ousness': (35, 4, None), |
||
1748 | 'eadings': (40.7, 4, None), |
||
1749 | 'oadings': (40.6, 4, None), |
||
1750 | 'ealings': (42.4, 4, None), |
||
1751 | 'ailings': (42.2, 4, None), |
||
1752 | }, |
||
1753 | 6: {'aceous': (1, 6, None), |
||
1754 | 'aining': (24, 3, None), |
||
1755 | 'acting': (25, 3, None), |
||
1756 | 'ttings': (26, 5, None), |
||
1757 | 'viding': (27, 3, 'e'), |
||
1758 | 'ssings': (37, 4, None), |
||
1759 | 'ulting': (38, 3, None), |
||
1760 | 'eading': (40.7, 3, None), |
||
1761 | 'oading': (40.6, 3, None), |
||
1762 | 'edings': (40.5, 4, None), |
||
1763 | 'ddings': (40.4, 5, None), |
||
1764 | 'ldings': (40.3, 4, None), |
||
1765 | 'rdings': (40.2, 4, None), |
||
1766 | 'ndings': (40.1, 4, None), |
||
1767 | 'llings': (41, 5, None), |
||
1768 | 'ealing': (42.4, 3, None), |
||
1769 | 'olings': (42.3, 4, None), |
||
1770 | 'ailing': (42.2, 3, None), |
||
1771 | 'elings': (42.1, 4, None), |
||
1772 | 'mmings': (44.3, 5, None), |
||
1773 | 'ngings': (45.2, 4, None), |
||
1774 | 'ggings': (45.1, 5, None), |
||
1775 | 'stings': (47, 4, None), |
||
1776 | 'etings': (48.4, 4, None), |
||
1777 | 'ntings': (48.2, 4, None), |
||
1778 | 'irings': (54.4, 4, 'e'), |
||
1779 | 'urings': (54.3, 4, 'e'), |
||
1780 | 'ncings': (54.2, 4, 'e'), |
||
1781 | 'things': (58.1, 1, None), |
||
1782 | }, |
||
1783 | 5: {'iases': (11.4, 2, None), |
||
1784 | 'ained': (13.6, 2, None), |
||
1785 | 'erned': (13.5, 2, None), |
||
1786 | 'ifted': (14, 2, None), |
||
1787 | 'ected': (15, 2, None), |
||
1788 | 'vided': (16, 1, None), |
||
1789 | 'erred': (19, 3, None), |
||
1790 | 'urred': (20.5, 3, None), |
||
1791 | 'lored': (20.4, 2, None), |
||
1792 | 'eared': (20.3, 2, None), |
||
1793 | 'tored': (20.2, 1, None), |
||
1794 | 'noted': (22.4, 1, None), |
||
1795 | 'leted': (22.3, 1, None), |
||
1796 | 'anges': (23, 1, None), |
||
1797 | 'tting': (26, 4, None), |
||
1798 | 'ulted': (32, 2, None), |
||
1799 | 'uming': (33, 3, 'e'), |
||
1800 | 'rabed': (36.1, 1, None), |
||
1801 | 'rebed': (36.1, 1, None), |
||
1802 | 'ribed': (36.1, 1, None), |
||
1803 | 'robed': (36.1, 1, None), |
||
1804 | 'rubed': (36.1, 1, None), |
||
1805 | 'ssing': (37, 3, None), |
||
1806 | 'vings': (39, 4, 'e'), |
||
1807 | 'eding': (40.5, 3, None), |
||
1808 | 'dding': (40.4, 4, None), |
||
1809 | 'lding': (40.3, 3, None), |
||
1810 | 'rding': (40.2, 3, None), |
||
1811 | 'nding': (40.1, 3, None), |
||
1812 | 'dings': (40, 4, 'e'), |
||
1813 | 'lling': (41, 4, None), |
||
1814 | 'oling': (42.3, 3, None), |
||
1815 | 'eling': (42.1, 3, None), |
||
1816 | 'lings': (42, 4, 'e'), |
||
1817 | 'mming': (44.3, 4, None), |
||
1818 | 'rming': (44.2, 3, None), |
||
1819 | 'lming': (44.1, 3, None), |
||
1820 | 'mings': (44, 4, 'e'), |
||
1821 | 'nging': (45.2, 3, None), |
||
1822 | 'gging': (45.1, 4, None), |
||
1823 | 'gings': (45, 4, 'e'), |
||
1824 | 'aning': (46.6, 3, None), |
||
1825 | 'ening': (46.5, 3, None), |
||
1826 | 'gning': (46.4, 3, None), |
||
1827 | 'nning': (46.3, 4, None), |
||
1828 | 'oning': (46.2, 3, None), |
||
1829 | 'rning': (46.1, 3, None), |
||
1830 | 'sting': (47, 3, None), |
||
1831 | 'eting': (48.4, 3, None), |
||
1832 | 'pting': (48.3, 3, None), |
||
1833 | 'nting': (48.2, 3, None), |
||
1834 | 'cting': (48.1, 3, None), |
||
1835 | 'tings': (48, 4, 'e'), |
||
1836 | 'iring': (54.4, 3, 'e'), |
||
1837 | 'uring': (54.3, 3, 'e'), |
||
1838 | 'ncing': (54.2, 3, 'e'), |
||
1839 | 'sings': (54, 4, 'e'), |
||
1840 | # 'lling': (55, 3, None), # masked by 41 |
||
1841 | 'ating': (57, 3, 'e'), |
||
1842 | 'thing': (58.1, 0, None), |
||
1843 | }, |
||
1844 | 4: {'eeds': (7, 1, None), |
||
1845 | 'uses': (11.3, 1, None), |
||
1846 | 'sses': (11.2, 2, None), |
||
1847 | 'eses': (11.1, 2, 'is'), |
||
1848 | 'tled': (12.5, 1, None), |
||
1849 | 'pled': (12.4, 1, None), |
||
1850 | 'bled': (12.3, 1, None), |
||
1851 | 'eled': (12.2, 2, None), |
||
1852 | 'lled': (12.1, 2, None), |
||
1853 | 'ened': (13.7, 2, None), |
||
1854 | 'rned': (13.4, 2, None), |
||
1855 | 'nned': (13.3, 3, None), |
||
1856 | 'oned': (13.2, 2, None), |
||
1857 | 'gned': (13.1, 2, None), |
||
1858 | 'ered': (20.1, 2, None), |
||
1859 | 'reds': (20, 2, None), |
||
1860 | 'tted': (21, 3, None), |
||
1861 | 'uted': (22.2, 1, None), |
||
1862 | 'ated': (22.1, 1, None), |
||
1863 | 'ssed': (28, 2, None), |
||
1864 | 'umed': (31, 1, None), |
||
1865 | 'beds': (36, 3, None), |
||
1866 | 'ving': (39, 3, 'e'), |
||
1867 | 'ding': (40, 3, 'e'), |
||
1868 | 'ling': (42, 3, 'e'), |
||
1869 | 'nged': (43.2, 1, None), |
||
1870 | 'gged': (43.1, 3, None), |
||
1871 | 'ming': (44, 3, 'e'), |
||
1872 | 'ging': (45, 3, 'e'), |
||
1873 | 'ning': (46, 3, 'e'), |
||
1874 | 'ting': (48, 3, 'e'), |
||
1875 | # 'ssed': (49, 2, None), # masked by 28 |
||
1876 | # 'lled': (53, 2, None), # masked by 12.1 |
||
1877 | 'zing': (54.1, 3, 'e'), |
||
1878 | 'sing': (54, 3, 'e'), |
||
1879 | 'lves': (60.1, 3, 'f'), |
||
1880 | 'aped': (61.3, 1, None), |
||
1881 | 'uded': (61.2, 1, None), |
||
1882 | 'oded': (61.1, 1, None), |
||
1883 | # 'ated': (61, 1, None), # masked by 22.1 |
||
1884 | 'ones': (63.6, 1, None), |
||
1885 | 'izes': (63.5, 1, None), |
||
1886 | 'ures': (63.4, 1, None), |
||
1887 | 'ines': (63.3, 1, None), |
||
1888 | 'ides': (63.2, 1, None), |
||
1889 | }, |
||
1890 | 3: {'ces': (2, 1, None), |
||
1891 | 'sis': (4, 0, None), |
||
1892 | 'tis': (5, 0, None), |
||
1893 | 'eed': (7, 0, None), |
||
1894 | 'ued': (8, 1, None), |
||
1895 | 'ues': (9, 1, None), |
||
1896 | 'ees': (10, 1, None), |
||
1897 | 'ses': (11, 1, None), |
||
1898 | 'led': (12, 2, None), |
||
1899 | 'ned': (13, 1, None), |
||
1900 | 'ved': (17, 1, None), |
||
1901 | 'ced': (18, 1, None), |
||
1902 | 'red': (20, 1, None), |
||
1903 | 'ted': (22, 2, None), |
||
1904 | 'sed': (29, 1, None), |
||
1905 | 'bed': (36, 2, None), |
||
1906 | 'ged': (43, 1, None), |
||
1907 | 'les': (50, 1, None), |
||
1908 | 'tes': (51, 1, None), |
||
1909 | 'zed': (52, 1, None), |
||
1910 | 'ied': (56, 3, 'y'), |
||
1911 | 'ies': (59, 3, 'y'), |
||
1912 | 'ves': (60, 1, None), |
||
1913 | 'pes': (63.8, 1, None), |
||
1914 | 'mes': (63.7, 1, None), |
||
1915 | 'ges': (63.1, 1, None), |
||
1916 | 'ous': (65, 0, None), |
||
1917 | 'ums': (66, 0, None), |
||
1918 | }, |
||
1919 | 2: {'cs': (3, 0, None), |
||
1920 | 'ss': (6, 0, None), |
||
1921 | 'es': (63, 2, None), |
||
1922 | 'is': (64, 2, 'e'), |
||
1923 | 'us': (67, 0, None), |
||
1924 | }} |
||
1925 | |||
1926 | if var == 'Perl': |
||
1927 | perl_deletions = {7: ['eadings', 'oadings', 'ealings', 'ailings'], |
||
1928 | 6: ['ttings', 'ssings', 'edings', 'ddings', |
||
1929 | 'ldings', 'rdings', 'ndings', 'llings', |
||
1930 | 'olings', 'elings', 'mmings', 'ngings', |
||
1931 | 'ggings', 'stings', 'etings', 'ntings', |
||
1932 | 'irings', 'urings', 'ncings', 'things'], |
||
1933 | 5: ['vings', 'dings', 'lings', 'mings', 'gings', |
||
1934 | 'tings', 'sings'], |
||
1935 | 4: ['eeds', 'reds', 'beds']} |
||
1936 | |||
1937 | # Delete the above rules from rule_table |
||
1938 | for del_len in perl_deletions: |
||
1939 | for term in perl_deletions[del_len]: |
||
1940 | del rule_table[del_len][term] |
||
1941 | |||
1942 | elif var == 'Adams': |
||
1943 | adams_additions = {6: {'chited': (22.8, 1, None)}, |
||
1944 | 5: {'dying': (58.2, 4, 'ie'), |
||
1945 | 'tying': (58.2, 4, 'ie'), |
||
1946 | 'vited': (22.6, 1, None), |
||
1947 | 'mited': (22.5, 1, None), |
||
1948 | 'vided': (22.9, 1, None), |
||
1949 | 'mided': (22.10, 1, None), |
||
1950 | 'lying': (58.2, 4, 'ie'), |
||
1951 | 'arred': (19.1, 3, None), |
||
1952 | }, |
||
1953 | 4: {'ited': (22.7, 2, None), |
||
1954 | 'oked': (31.1, 1, None), |
||
1955 | 'aked': (31.1, 1, None), |
||
1956 | 'iked': (31.1, 1, None), |
||
1957 | 'uked': (31.1, 1, None), |
||
1958 | 'amed': (31, 1, None), |
||
1959 | 'imed': (31, 1, None), |
||
1960 | 'does': (31.2, 2, None), |
||
1961 | }, |
||
1962 | 3: {'oed': (31.3, 1, None), |
||
1963 | 'oes': (31.2, 1, None), |
||
1964 | 'kes': (63.1, 1, None), |
||
1965 | 'des': (63.10, 1, None), |
||
1966 | 'res': (63.9, 1, None), |
||
1967 | }} |
||
1968 | |||
1969 | # Add the above additional rules to rule_table |
||
1970 | for del_len in adams_additions: |
||
1971 | rule_table[del_len] = dict(rule_table[del_len], |
||
1972 | **adams_additions[del_len]) |
||
1973 | # Add additional problem word |
||
1974 | problem_words.add('menses') |
||
1975 | |||
1976 | def _stem_with_duplicate_character_check(word, del_len): |
||
1977 | if word[-1] == 's': |
||
1978 | del_len += 1 |
||
1979 | stemmed_word = word[:-del_len] |
||
1980 | if re.match(r'.*(\w)\1$', stemmed_word): |
||
1981 | stemmed_word = stemmed_word[:-1] |
||
1982 | return stemmed_word |
||
1983 | |||
1984 | def _stem(word): |
||
1985 | stemmed_word = word |
||
1986 | rule_no = 0 |
||
1987 | |||
1988 | if not word: |
||
1989 | return word, 0 |
||
1990 | if word in problem_words: |
||
1991 | return word, 90 |
||
1992 | if max_word_length and len(word) > max_word_length: |
||
1993 | return word, 95 |
||
1994 | |||
1995 | if "'" in word: |
||
1996 | if word[-2:] in {"'s", "'S"}: |
||
1997 | stemmed_word = word[:-2] |
||
1998 | if word[-1:] == "'": |
||
1999 | stemmed_word = word[:-1] |
||
2000 | stemmed_word = stemmed_word.replace("n't", 'not') |
||
2001 | stemmed_word = stemmed_word.replace("'ve", 'have') |
||
2002 | stemmed_word = stemmed_word.replace("'re", 'are') |
||
2003 | stemmed_word = stemmed_word.replace("'m", 'am') |
||
2004 | return stemmed_word, 94 |
||
2005 | |||
2006 | if word.isdigit(): |
||
2007 | return word, 90.3 |
||
2008 | else: |
||
2009 | hyphen = word.find('-') |
||
2010 | if hyphen > 0 and hyphen < len(word): |
||
2011 | if word[:hyphen].isalpha() and word[hyphen+1:].isalpha(): |
||
2012 | return word, 90.2 |
||
2013 | else: |
||
2014 | return word, 90.1 |
||
2015 | elif '_' in word: |
||
2016 | return word, 90 |
||
2017 | elif word[-1] == 's' and word[:-1].isupper(): |
||
2018 | if var == 'Adams' and len(word)-1 > max_acro_length: |
||
2019 | return word, 96 |
||
2020 | return word[:-1], 91.1 |
||
2021 | elif word.isupper(): |
||
2022 | if var == 'Adams' and len(word) > max_acro_length: |
||
2023 | return word, 96 |
||
2024 | return word, 91 |
||
2025 | elif re.match(r'^.*[A-Z].*[A-Z].*$', word): |
||
2026 | return word, 92 |
||
2027 | elif word[0].isupper(): |
||
2028 | return word, 93 |
||
2029 | elif var == 'Adams' and re.match(r'^[a-z]{1}(|[rl])(ing|ed)$', |
||
2030 | word): |
||
2031 | return word, 97 |
||
2032 | |||
2033 | for n in range(7, 1, -1): |
||
2034 | if word[-n:] in rule_table[n]: |
||
2035 | rule_no, del_len, add_str = rule_table[n][word[-n:]] |
||
2036 | if del_len: |
||
2037 | stemmed_word = word[:-del_len] |
||
2038 | else: |
||
2039 | stemmed_word = word |
||
2040 | if add_str: |
||
2041 | stemmed_word += add_str |
||
2042 | break |
||
2043 | |||
2044 | if not rule_no: |
||
2045 | if re.match(r'.*\w\wings?$', word): # rule 58 |
||
2046 | stemmed_word = _stem_with_duplicate_character_check(word, 3) |
||
2047 | rule_no = 58 |
||
2048 | elif re.match(r'.*\w\weds?$', word): # rule 62 |
||
2049 | stemmed_word = _stem_with_duplicate_character_check(word, 2) |
||
2050 | rule_no = 62 |
||
2051 | elif word[-1] == 's': # rule 68 |
||
2052 | stemmed_word = word[:-1] |
||
2053 | rule_no = 68 |
||
2054 | |||
2055 | return stemmed_word, rule_no |
||
2056 | |||
2057 | stem, rule_no = _stem(word) |
||
2058 | if return_rule_no: |
||
2059 | return stem, rule_no |
||
2060 | return stem |
||
2061 | |||
2062 | |||
2063 | def paice_husk(word): |
||
2064 | """Return Paice-Husk stem. |
||
2065 | |||
2066 | Implementation of the Paice-Husk Stemmer, also known as the Lancaster |
||
2067 | Stemmer, developed by Chris Paice, with the assistance of Gareth Husk |
||
2068 | |||
2069 | This is based on the algorithm's description in: |
||
2070 | Paice, Chris D. 1990. "Another stemmer." ACM SIGIR Forum 24:3, Fall 1990. |
||
2071 | 56-61. doi:10.1145/101306.101310. |
||
2072 | |||
2073 | :param word: the word to calculate the stem of |
||
2074 | :returns: word stem |
||
2075 | :rtype: str |
||
2076 | """ |
||
2077 | rule_table = {6: {'ifiabl': (False, 6, None, True), |
||
2078 | 'plicat': (False, 4, 'y', True)}, |
||
2079 | 5: {'guish': (False, 5, 'ct', True), |
||
2080 | 'sumpt': (False, 2, None, True), |
||
2081 | 'istry': (False, 5, None, True)}, |
||
2082 | 4: {'ytic': (False, 3, 's', True), |
||
2083 | 'ceed': (False, 2, 'ss', True), |
||
2084 | 'hood': (False, 4, None, False), |
||
2085 | 'lief': (False, 1, 'v', True), |
||
2086 | 'verj': (False, 1, 't', True), |
||
2087 | 'misj': (False, 2, 't', True), |
||
2088 | 'iabl': (False, 4, 'y', True), |
||
2089 | 'iful': (False, 4, 'y', True), |
||
2090 | 'sion': (False, 4, 'j', False), |
||
2091 | 'xion': (False, 4, 'ct', True), |
||
2092 | 'ship': (False, 4, None, False), |
||
2093 | 'ness': (False, 4, None, False), |
||
2094 | 'ment': (False, 4, None, False), |
||
2095 | 'ript': (False, 2, 'b', True), |
||
2096 | 'orpt': (False, 2, 'b', True), |
||
2097 | 'duct': (False, 1, None, True), |
||
2098 | 'cept': (False, 2, 'iv', True), |
||
2099 | 'olut': (False, 2, 'v', True), |
||
2100 | 'sist': (False, 0, None, True)}, |
||
2101 | 3: {'ied': (False, 3, 'y', False), |
||
2102 | 'eed': (False, 1, None, True), |
||
2103 | 'ing': (False, 3, None, False), |
||
2104 | 'iag': (False, 3, 'y', True), |
||
2105 | 'ish': (False, 3, None, False), |
||
2106 | 'fuj': (False, 1, 's', True), |
||
2107 | 'hej': (False, 1, 'r', True), |
||
2108 | 'abl': (False, 3, None, False), |
||
2109 | 'ibl': (False, 3, None, True), |
||
2110 | 'bil': (False, 2, 'l', False), |
||
2111 | 'ful': (False, 3, None, False), |
||
2112 | 'ial': (False, 3, None, False), |
||
2113 | 'ual': (False, 3, None, False), |
||
2114 | 'ium': (False, 3, None, True), |
||
2115 | 'ism': (False, 3, None, False), |
||
2116 | 'ion': (False, 3, None, False), |
||
2117 | 'ian': (False, 3, None, False), |
||
2118 | 'een': (False, 0, None, True), |
||
2119 | 'ear': (False, 0, None, True), |
||
2120 | 'ier': (False, 3, 'y', False), |
||
2121 | 'ies': (False, 3, 'y', False), |
||
2122 | 'sis': (False, 2, None, True), |
||
2123 | 'ous': (False, 3, None, False), |
||
2124 | 'ent': (False, 3, None, False), |
||
2125 | 'ant': (False, 3, None, False), |
||
2126 | 'ist': (False, 3, None, False), |
||
2127 | 'iqu': (False, 3, None, True), |
||
2128 | 'ogu': (False, 1, None, True), |
||
2129 | 'siv': (False, 3, 'j', False), |
||
2130 | 'eiv': (False, 0, None, True), |
||
2131 | 'bly': (False, 1, None, False), |
||
2132 | 'ily': (False, 3, 'y', False), |
||
2133 | 'ply': (False, 0, None, True), |
||
2134 | 'ogy': (False, 1, None, True), |
||
2135 | 'phy': (False, 1, None, True), |
||
2136 | 'omy': (False, 1, None, True), |
||
2137 | 'opy': (False, 1, None, True), |
||
2138 | 'ity': (False, 3, None, False), |
||
2139 | 'ety': (False, 3, None, False), |
||
2140 | 'lty': (False, 2, None, True), |
||
2141 | 'ary': (False, 3, None, False), |
||
2142 | 'ory': (False, 3, None, False), |
||
2143 | 'ify': (False, 3, None, True), |
||
2144 | 'ncy': (False, 2, 't', False), |
||
2145 | 'acy': (False, 3, None, False)}, |
||
2146 | 2: {'ia': (True, 2, None, True), |
||
2147 | 'bb': (False, 1, None, True), |
||
2148 | 'ic': (False, 2, None, False), |
||
2149 | 'nc': (False, 1, 't', False), |
||
2150 | 'dd': (False, 1, None, True), |
||
2151 | 'ed': (False, 2, None, False), |
||
2152 | 'if': (False, 2, None, False), |
||
2153 | 'ag': (False, 2, None, False), |
||
2154 | 'gg': (False, 1, None, True), |
||
2155 | 'th': (True, 2, None, True), |
||
2156 | 'ij': (False, 1, 'd', True), |
||
2157 | 'uj': (False, 1, 'd', True), |
||
2158 | 'oj': (False, 1, 'd', True), |
||
2159 | 'nj': (False, 1, 'd', True), |
||
2160 | 'cl': (False, 1, None, True), |
||
2161 | 'ul': (False, 2, None, True), |
||
2162 | 'al': (False, 2, None, False), |
||
2163 | 'll': (False, 1, None, True), |
||
2164 | 'um': (True, 2, None, True), |
||
2165 | 'mm': (False, 1, None, True), |
||
2166 | 'an': (False, 2, None, False), |
||
2167 | 'en': (False, 2, None, False), |
||
2168 | 'nn': (False, 1, None, True), |
||
2169 | 'pp': (False, 1, None, True), |
||
2170 | 'er': (False, 2, None, False), |
||
2171 | 'ar': (False, 2, None, True), |
||
2172 | 'or': (False, 2, None, False), |
||
2173 | 'ur': (False, 2, None, False), |
||
2174 | 'rr': (False, 1, None, True), |
||
2175 | 'tr': (False, 1, None, False), |
||
2176 | 'is': (False, 2, None, False), |
||
2177 | 'ss': (False, 0, None, True), |
||
2178 | 'us': (True, 2, None, True), |
||
2179 | 'at': (False, 2, None, False), |
||
2180 | 'tt': (False, 1, None, True), |
||
2181 | 'iv': (False, 2, None, False), |
||
2182 | 'ly': (False, 2, None, False), |
||
2183 | 'iz': (False, 2, None, False), |
||
2184 | 'yz': (False, 1, 's', True)}, |
||
2185 | 1: {'a': (True, 1, None, True), |
||
2186 | 'e': (False, 1, None, False), |
||
2187 | 'i': ((True, 1, None, True), (False, 1, 'y', False)), |
||
2188 | 'j': (False, 1, 's', True), |
||
2189 | 's': ((True, 1, None, False), (False, 0, None, True))}} |
||
2190 | |||
2191 | def _has_vowel(word): |
||
2192 | for char in word: |
||
2193 | if char in {'a', 'e', 'i', 'o', 'u', 'y'}: |
||
2194 | return True |
||
2195 | return False |
||
2196 | |||
2197 | def _acceptable(word): |
||
2198 | if word and word[0] in {'a', 'e', 'i', 'o', 'u'}: |
||
2199 | return len(word) > 1 |
||
2200 | return len(word) > 2 and _has_vowel(word[1:]) |
||
2201 | |||
2202 | def _apply_rule(word, rule, intact): |
||
2203 | old_word = word |
||
2204 | only_intact, del_len, add_str, set_terminate = rule |
||
2205 | # print(word, word[-n:], rule) |
||
2206 | |||
2207 | if (not only_intact) or (intact and only_intact): |
||
2208 | if del_len: |
||
2209 | word = word[:-del_len] |
||
2210 | if add_str: |
||
2211 | word += add_str |
||
2212 | else: |
||
2213 | return word, False, intact, terminate |
||
2214 | |||
2215 | if _acceptable(word): |
||
2216 | return word, True, False, set_terminate |
||
2217 | else: |
||
2218 | return old_word, False, intact, terminate |
||
2219 | |||
2220 | terminate = False |
||
2221 | intact = True |
||
2222 | while not terminate: |
||
2223 | for n in range(6, 0, -1): |
||
2224 | if word[-n:] in rule_table[n]: |
||
2225 | accept = False |
||
2226 | if len(rule_table[n][word[-n:]]) < 4: |
||
2227 | for rule in rule_table[n][word[-n:]]: |
||
2228 | (word, accept, intact, |
||
2229 | terminate) = _apply_rule(word, rule, intact) |
||
2230 | if accept: |
||
2231 | break |
||
2232 | else: |
||
2233 | rule = rule_table[n][word[-n:]] |
||
2234 | (word, accept, intact, |
||
2235 | terminate) = _apply_rule(word, rule, intact) |
||
2236 | |||
2237 | if accept: |
||
2238 | break |
||
2239 | else: |
||
2240 | break |
||
2241 | |||
2242 | return word |
||
2243 |