chrislit /
abydos
| Conditions | 25 |
| Total Lines | 99 |
| Code Lines | 63 |
| Lines | 0 |
| Ratio | 0 % |
| Tests | 59 |
| CRAP Score | 25 |
| Changes | 0 | ||
Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.
For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.
Commonly applied refactorings include:
If many parameters/temporary variables are present:
Complex classes like abydos.distance._sift4.sift4_common() 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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| 99 | 1 | def sift4_common(src, tar, max_offset=5, max_distance=0): |
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| 100 | """Return the "common" Sift4 distance between two terms. |
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| 101 | |||
| 102 | This is an approximation of edit distance, described in |
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| 103 | :cite:`Zackwehdex:2014`. |
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| 104 | |||
| 105 | :param str src: source string for comparison |
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| 106 | :param str tar: target string for comparison |
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| 107 | :param max_offset: the number of characters to search for matching letters |
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| 108 | :param max_distance: the distance at which to stop and exit |
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| 109 | :returns: the Sift4 distance according to the common formula |
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| 110 | :rtype: int |
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| 111 | |||
| 112 | >>> sift4_common('cat', 'hat') |
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| 113 | 1 |
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| 114 | >>> sift4_common('Niall', 'Neil') |
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| 115 | 2 |
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| 116 | >>> sift4_common('Colin', 'Cuilen') |
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| 117 | 3 |
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| 118 | >>> sift4_common('ATCG', 'TAGC') |
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| 119 | 2 |
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| 120 | """ |
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| 121 | 1 | if not src: |
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| 122 | 1 | return len(tar) |
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| 123 | |||
| 124 | 1 | if not tar: |
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| 125 | 1 | return len(src) |
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| 126 | |||
| 127 | 1 | src_len = len(src) |
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| 128 | 1 | tar_len = len(tar) |
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| 129 | |||
| 130 | 1 | src_cur = 0 |
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| 131 | 1 | tar_cur = 0 |
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| 132 | 1 | lcss = 0 |
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| 133 | 1 | local_cs = 0 |
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| 134 | 1 | trans = 0 |
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| 135 | 1 | offset_arr = [] |
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| 136 | |||
| 137 | 1 | while (src_cur < src_len) and (tar_cur < tar_len): |
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| 138 | 1 | if src[src_cur] == tar[tar_cur]: |
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| 139 | 1 | local_cs += 1 |
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| 140 | 1 | is_trans = False |
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| 141 | 1 | i = 0 |
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| 142 | 1 | while i < len(offset_arr): |
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| 143 | 1 | ofs = offset_arr[i] |
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| 144 | 1 | if src_cur <= ofs['src_cur'] or tar_cur <= ofs['tar_cur']: |
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| 145 | 1 | is_trans = abs(tar_cur - src_cur) >= abs( |
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| 146 | ofs['tar_cur'] - ofs['src_cur'] |
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| 147 | ) |
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| 148 | 1 | if is_trans: |
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| 149 | 1 | trans += 1 |
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| 150 | 1 | elif not ofs['trans']: |
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| 151 | 1 | ofs['trans'] = True |
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| 152 | 1 | trans += 1 |
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| 153 | 1 | break |
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| 154 | 1 | elif src_cur > ofs['tar_cur'] and tar_cur > ofs['src_cur']: |
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| 155 | 1 | del offset_arr[i] |
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| 156 | else: |
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| 157 | 1 | i += 1 |
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| 158 | |||
| 159 | 1 | offset_arr.append( |
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| 160 | {'src_cur': src_cur, 'tar_cur': tar_cur, 'trans': is_trans} |
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| 161 | ) |
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| 162 | else: |
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| 163 | 1 | lcss += local_cs |
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| 164 | 1 | local_cs = 0 |
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| 165 | 1 | if src_cur != tar_cur: |
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| 166 | 1 | src_cur = tar_cur = min(src_cur, tar_cur) |
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| 167 | 1 | for i in range(max_offset): |
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| 168 | 1 | if not ((src_cur + i < src_len) or (tar_cur + i < tar_len)): |
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| 169 | 1 | break |
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| 170 | 1 | if (src_cur + i < src_len) and ( |
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| 171 | src[src_cur + i] == tar[tar_cur] |
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| 172 | ): |
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| 173 | 1 | src_cur += i - 1 |
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| 174 | 1 | tar_cur -= 1 |
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| 175 | 1 | break |
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| 176 | 1 | if (tar_cur + i < tar_len) and ( |
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| 177 | src[src_cur] == tar[tar_cur + i] |
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| 178 | ): |
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| 179 | 1 | src_cur -= 1 |
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| 180 | 1 | tar_cur += i - 1 |
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| 181 | 1 | break |
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| 182 | |||
| 183 | 1 | src_cur += 1 |
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| 184 | 1 | tar_cur += 1 |
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| 185 | |||
| 186 | 1 | if max_distance: |
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| 187 | 1 | temporary_distance = max(src_cur, tar_cur) - lcss + trans |
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| 188 | 1 | if temporary_distance >= max_distance: |
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| 189 | 1 | return round(temporary_distance) |
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| 190 | |||
| 191 | 1 | if (src_cur >= src_len) or (tar_cur >= tar_len): |
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| 192 | 1 | lcss += local_cs |
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| 193 | 1 | local_cs = 0 |
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| 194 | 1 | src_cur = tar_cur = min(src_cur, tar_cur) |
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| 195 | |||
| 196 | 1 | lcss += local_cs |
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| 197 | 1 | return round(max(src_len, tar_len) - lcss + trans) |
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| 198 | |||
| 255 |
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