Complex classes like Collection 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. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
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.
While breaking up the class, it is a good idea to analyze how other classes use Collection, and based on these observations, apply Extract Interface, too.
1 | <?php |
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5 | class Collection implements \Iterator, \ArrayAccess, \Serializable, \Countable |
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6 | { |
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7 | protected $array = null; |
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8 | protected $stack = []; |
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9 | protected $iterator = null; |
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10 | protected $key = null; |
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11 | protected $val = null; |
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12 | |||
13 | 4 | protected static function rangeGenerator($low, $high, $step = 1) |
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14 | { |
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15 | 4 | $k = -1; |
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16 | 4 | for ($i = $low; $i <= $high; $i += $step) { |
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17 | 4 | yield ++$k => $i; |
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18 | } |
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19 | 4 | } |
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20 | /** |
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21 | * Create a collection based on a range generator |
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22 | * @param int|float $low start value |
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23 | * @param int|float $high end value |
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24 | * @param int|float $step increment |
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25 | * @return Collection |
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26 | */ |
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27 | 4 | public static function range($low, $high, $step = 1) : Collection |
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28 | { |
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29 | 4 | return new static(static::rangeGenerator($low, $high, $step)); |
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30 | } |
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31 | /** |
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32 | * A static alias of the __constructor |
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33 | * @param mixed $input Anything iterable |
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34 | * @return Collection |
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35 | */ |
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36 | 51 | public static function from($input) : Collection |
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37 | { |
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38 | 51 | return new static($input); |
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39 | } |
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40 | /** |
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41 | * Create an instance |
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42 | * @param mixed $input Anything iterable |
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43 | */ |
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44 | 55 | public function __construct($input = []) |
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45 | { |
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46 | 55 | if (is_object($input)) { |
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47 | 28 | if ($input instanceof \Iterator) { |
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48 | 5 | $this->array = $input; |
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49 | 5 | $this->iterator = $input; |
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50 | 23 | } else if ($input instanceof self) { |
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51 | $this->array = $input->toArray(); |
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52 | } else { |
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53 | 23 | $input = get_object_vars($input); |
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54 | } |
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55 | } |
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56 | 55 | if (is_array($input)) { |
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57 | 51 | $this->array = new \ArrayObject($input); |
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58 | 51 | $this->iterator = $this->array->getIterator(); |
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59 | } |
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60 | 55 | } |
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61 | public function __clone() |
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62 | { |
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63 | $this->array = new \ArrayObject(iterator_to_array($this)); |
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64 | $this->stack = []; |
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65 | $this->iterator = $this->array->getIterator(); |
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66 | } |
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67 | 1 | public function __toString() |
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68 | { |
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69 | 1 | return implode(', ', $this->toArray()); |
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70 | } |
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71 | 1 | public function serialize() { |
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72 | 1 | return serialize($this->toArray()); |
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73 | } |
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74 | 1 | public function unserialize($array) { |
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75 | 1 | $this->array = new \ArrayObject(unserialize($array)); |
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76 | 1 | $this->stack = []; |
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77 | 1 | $this->iterator = $this->array->getIterator(); |
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78 | 1 | } |
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79 | |||
80 | /** |
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81 | * Applies all pending operations |
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82 | * @return $this |
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83 | */ |
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84 | 45 | public function squash() : Collection |
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85 | { |
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86 | 45 | $this->array = new \ArrayObject(iterator_to_array($this)); |
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87 | 45 | $this->stack = []; |
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88 | 45 | $this->iterator = $this->array->getIterator(); |
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89 | 45 | return $this; |
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90 | } |
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91 | /** |
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92 | * Get an actual array from the collection |
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93 | * @return array |
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94 | */ |
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95 | 44 | public function toArray() : array |
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96 | { |
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97 | 44 | $this->squash(); |
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98 | 44 | return $this->array->getArrayCopy(); |
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99 | } |
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100 | /** |
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101 | * Gets the first value in the collection or null if empty |
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102 | * @return mixed |
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103 | */ |
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104 | 3 | public function value() |
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105 | { |
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106 | 3 | foreach ($this as $v) { |
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107 | 3 | return $v; |
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108 | } |
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109 | 1 | return null; |
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110 | } |
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111 | |||
112 | // iterator |
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113 | 51 | public function key() |
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114 | { |
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115 | 51 | return $this->key; |
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116 | } |
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117 | 54 | public function current() |
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118 | { |
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119 | 54 | return $this->val; |
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120 | } |
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121 | 54 | public function rewind() |
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122 | { |
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123 | 54 | return $this->iterator->rewind(); |
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124 | } |
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125 | 53 | public function next() |
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126 | { |
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127 | 53 | return $this->iterator->next(); |
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128 | } |
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129 | 54 | public function valid() |
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130 | { |
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131 | 54 | while ($this->iterator->valid()) { |
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132 | 54 | $this->val = $this->iterator->current(); |
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133 | 54 | $this->key = $this->iterator->key(); |
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134 | 54 | $con = false; |
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135 | 54 | foreach ($this->stack as $action) { |
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136 | 12 | if ($action[0] === 'filter') { |
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137 | 8 | if (!call_user_func($action[1], $this->val, $this->key, $this)) { |
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138 | 8 | $con = true; |
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139 | 8 | break; |
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140 | } |
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141 | } |
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142 | 12 | if ($action[0] === 'map') { |
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143 | 5 | $this->val = call_user_func($action[1], $this->val, $this->key, $this); |
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144 | } |
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145 | 12 | if ($action[0] === 'mapKey') { |
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146 | 12 | $this->key = call_user_func($action[1], $this->val, $this->key, $this); |
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147 | } |
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148 | } |
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149 | 54 | if ($con) { |
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150 | 8 | $this->iterator->next(); |
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151 | 8 | continue; |
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152 | } |
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153 | 54 | return true; |
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154 | } |
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155 | 54 | return false; |
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156 | } |
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157 | |||
158 | // array access |
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159 | 1 | public function offsetGet($offset) |
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160 | { |
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161 | 1 | if (count($this->stack) || !($this->array instanceof \ArrayAccess)) { |
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162 | $this->squash(); |
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163 | } |
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164 | 1 | return $this->squash()->iterator->offsetGet($offset); |
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165 | } |
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166 | 1 | public function offsetExists($offset) |
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167 | { |
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168 | 1 | if (count($this->stack) || !($this->array instanceof \ArrayAccess)) { |
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169 | $this->squash(); |
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170 | } |
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171 | 1 | return $this->squash()->iterator->offsetExists($offset); |
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172 | } |
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173 | 1 | public function offsetUnset($offset) |
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174 | { |
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175 | 1 | return $this->squash()->iterator->offsetUnset($offset); |
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176 | } |
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177 | 1 | public function offsetSet($offset, $value) |
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178 | { |
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179 | 1 | return $this->squash()->iterator->offsetSet($offset, $value); |
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180 | } |
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181 | /** |
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182 | * Get the collection length |
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183 | * @return int |
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184 | */ |
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185 | 1 | public function count() |
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186 | { |
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187 | 1 | if (count($this->stack) || !($this->array instanceof \Countable)) { |
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188 | $this->squash(); |
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189 | } |
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190 | 1 | return $this->array->count(); |
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191 | } |
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192 | |||
193 | // mutators |
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194 | /** |
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195 | * Filter values from the collection based on a predicate. The callback will receive the value, key and collection |
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196 | * @param callable $iterator the predicate |
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197 | * @return $this |
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198 | */ |
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199 | 8 | public function filter(callable $iterator) : Collection |
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204 | /** |
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205 | * Pass all values of the collection through a mutator callable, which will receive the value, key and collection |
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206 | * @param callable $iterator the mutator |
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207 | * @return $this |
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208 | */ |
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209 | 5 | public function map(callable $iterator) : Collection |
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214 | /** |
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215 | * Pass all values of the collection through a key mutator callable, which will receive the value, key and collection |
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216 | * @param callable $iterator the mutator |
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217 | * @return $this |
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218 | */ |
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219 | 1 | public function mapKey(callable $iterator) : Collection |
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220 | { |
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221 | 1 | $this->stack[] = [ 'mapKey', $iterator ]; |
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222 | 1 | return $this; |
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223 | } |
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224 | /** |
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225 | * Clone the current collection and return it. |
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226 | * @return Collection |
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227 | */ |
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228 | public function clone() : Collection |
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229 | { |
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230 | 1 | return new static($this->toArray()); |
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231 | } |
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232 | /** |
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233 | * Remove all falsy values from the collection (uses filter internally). |
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234 | * @return $this |
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235 | */ |
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236 | 1 | public function compact() : Collection |
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237 | { |
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242 | /** |
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243 | * Exclude all listed values from the collection (uses filter internally). |
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244 | * @param iterable $values the values to exclude |
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245 | * @return $this |
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246 | */ |
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247 | 3 | public function difference($values) : Collection |
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260 | /** |
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261 | * Append more values to the collection |
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262 | * @param iterable $source the values to add |
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263 | * @return Collection |
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264 | */ |
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265 | 2 | public function extend($source) : Collection |
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272 | /** |
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273 | * Append more values to the collection |
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274 | * @param iterable $source the values to add |
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275 | * @return Collection |
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276 | */ |
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277 | 1 | public function merge($source) : Collection |
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281 | /** |
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282 | * Perform a shallow flatten of the collection |
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283 | * @return Collection |
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284 | */ |
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285 | 1 | public function flatten() : Collection |
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294 | /** |
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295 | * Group by a key (if a callable is used - return the value to group by) |
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296 | * @param string|callable $iterator the key to group by |
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297 | * @return Collection |
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298 | */ |
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299 | 1 | public function groupBy($iterator) : Collection |
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308 | /** |
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309 | * Get the first X items from the collection |
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310 | * @param int $count the number of items to include (defaults to 1) |
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311 | * @return Collection |
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312 | */ |
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313 | 1 | public function first(int $count = 1) : Collection |
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325 | /** |
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326 | * Get the first X items from the collection |
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327 | * @param int $count the number of items to include (defaults to 1) |
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328 | * @return Collection |
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329 | */ |
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330 | 1 | public function head(int $count = 1) : Collection |
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334 | /** |
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335 | * Get the last X items from the collection |
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336 | * @param int $count the number of items to include (defaults to 1) |
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337 | * @return Collection |
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338 | */ |
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339 | 2 | public function last(int $count = 1) : Collection |
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344 | /** |
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345 | * Get the first X items from the collection |
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346 | * @param int $count the number of items to include (defaults to 1) |
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347 | * @return Collection |
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348 | */ |
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349 | 1 | public function tail(int $count = 1) : Collection |
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353 | /** |
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354 | * Get all but the last X items from the collection |
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355 | * @param int $count the number of items to exclude (defaults to 1) |
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356 | * @return Collection |
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357 | */ |
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358 | 1 | public function initial(int $count = 1) : Collection |
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363 | /** |
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364 | * Get all but the first X items from the collection |
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365 | * @param int $count the number of items to exclude (defaults to 1) |
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366 | * @return Collection |
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367 | */ |
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368 | 1 | public function rest(int $count = 1) : Collection |
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373 | /** |
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374 | * Execute a callable for each item in the collection (does not modify the collection) |
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375 | * @param callable $iterator the callable to execute |
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376 | * @return $this |
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377 | */ |
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378 | 1 | public function each(callable $iterator) : Collection |
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385 | /** |
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386 | * Execute a callable for each item in the collection (does not modify the collection) |
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387 | * @param callable $iterator the callable to execute |
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388 | * @return $this |
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389 | */ |
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390 | 1 | public function invoke(callable $iterator) : Collection |
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394 | /** |
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395 | * Get all the collection keys |
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396 | * @return $this |
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397 | */ |
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398 | public function keys() : Collection |
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402 | /** |
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403 | * Pluck a value from each object (uses map internally) |
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404 | * @param string|int $key the key to extract |
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405 | * @return $this |
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406 | */ |
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407 | 2 | public function pluck($key) : Collection |
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415 | /** |
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416 | * Intersect the collection with another iterable (uses filter internally) |
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417 | * @param interable $values the data to intersect with |
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418 | * @return $this |
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419 | */ |
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420 | 1 | public function intersection($values) : Collection |
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433 | /** |
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434 | * Reject values on a given predicate (opposite of filter) |
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435 | * @param callable $iterator the predicate |
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436 | * @return $this |
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437 | */ |
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438 | 1 | public function reject(callable $iterator) : Collection |
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444 | /** |
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445 | * Shuffle the values in the collection |
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446 | * @return Collection |
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447 | */ |
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448 | 1 | public function shuffle() : Collection |
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459 | /** |
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460 | * Sort the collection using a standard sorting function |
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461 | * @param callable $iterator the sort function (must return -1, 0 or 1) |
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462 | * @return Collection |
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463 | */ |
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464 | 1 | public function sortBy(callable $iterator) : Collection |
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470 | /** |
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471 | * Inspect the whole collection (as an array) mid-chain |
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472 | * @param callable $iterator the callable to execute |
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473 | * @return $this |
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474 | */ |
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475 | 1 | public function tap(callable $iterator) : Collection |
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480 | /** |
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481 | * Modify the whole collection (as an array) mid-chain |
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482 | * @param callable $iterator the callable to execute |
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483 | * @return Collection |
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484 | */ |
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485 | 1 | public function thru(callable $iterator) : Collection |
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491 | /** |
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492 | * Leave only unique items in the collection |
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493 | * @return Collection |
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494 | */ |
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495 | 3 | public function unique() : Collection |
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506 | /** |
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507 | * Get only the values of the collection |
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508 | * @return Collection |
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509 | */ |
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510 | 3 | public function values() : Collection |
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514 | /** |
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515 | * Filter items from the collection using key => value pairs |
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516 | * @param array $properties the key => value to check for in each item |
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517 | * @param boolean $strict should the comparison be strict |
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518 | * @return $this |
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519 | */ |
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520 | public function where(array $properties, $strict = true) : Collection |
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532 | /** |
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533 | * Exclude all listed values from the collection (uses filter internally). |
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534 | * @param iterable $values the values to exclude |
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535 | * @return $this |
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536 | */ |
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537 | 2 | public function without($values) : Collection |
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541 | /** |
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542 | * Combine all the values from the collection with a key |
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543 | * @param iterable $keys the keys to use |
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544 | * @return Collection |
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545 | */ |
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546 | 2 | public function zip($keys) : Collection |
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553 | /** |
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554 | * Reverse the collection order |
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555 | * @return Collection |
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556 | */ |
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557 | 1 | public function reverse() : Collection |
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561 | |||
562 | // accessors |
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563 | /** |
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564 | * Do all of the items in the collection match a given criteria |
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565 | * @param callable $iterator the criteria - should return true / false |
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566 | * @return bool |
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567 | */ |
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568 | 1 | public function all(callable $iterator) : bool |
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577 | /** |
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578 | * Do any of the items in the collection match a given criteria |
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579 | * @param callable $iterator the criteria - should return true / false |
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580 | * @return bool |
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581 | */ |
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582 | 1 | public function any(callable $iterator) : bool |
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591 | /** |
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592 | * Does the collection contain a given value |
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593 | * @param mixed $needle the value to check for |
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594 | * @return bool |
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595 | */ |
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596 | 1 | public function contains($needle) : bool |
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605 | /** |
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606 | * Get the first element matching a given criteria (or null) |
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607 | * @param callable $iterator the filter criteria |
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608 | * @return mixed |
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609 | */ |
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610 | 1 | public function find(callable $iterator) |
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619 | /** |
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620 | * Get all the elements matching a given criteria (with the option to limit the number of results) |
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621 | * @param callable $iterator the search criteria |
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622 | * @param int|null $limit optional limit to the number of results (default to null - no limit) |
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623 | * @return Collection |
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624 | */ |
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625 | 1 | public function findAll(callable $iterator, int $limit = null) : Collection |
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638 | /** |
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639 | * Get the key corresponding to a value (or false) |
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640 | * @param mixed $needle the value to search for |
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641 | * @return mixed |
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642 | */ |
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643 | 1 | public function indexOf($needle) |
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647 | /** |
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648 | * Get the last key corresponding to a value (or false) |
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649 | * @param mixed $needle the value to search for |
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650 | * @return mixed |
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651 | */ |
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652 | 1 | public function lastIndexOf($needle) |
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662 | /** |
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663 | * Get the number of elements in the collection |
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664 | * @return int |
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665 | */ |
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666 | 1 | public function size() : int |
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670 | /** |
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671 | * Get the minimal item in the collection |
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672 | * @return mixed |
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673 | */ |
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674 | 1 | public function min() |
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686 | /** |
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687 | * Get the maximum item in the collection |
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688 | * @return mixed |
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689 | */ |
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690 | 1 | public function max() |
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702 | /** |
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703 | * Does the collection contain a given key |
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704 | * @param string|int $key the key to check |
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705 | * @return bool |
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706 | */ |
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707 | 1 | public function has($key) : bool |
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711 | /** |
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712 | * Reduce the collection to a single value |
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713 | * @param callable $iterator the reducer |
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714 | * @param mixed $initial the initial value |
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715 | * @return mixed the final value |
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716 | */ |
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717 | 1 | public function reduce(callable $iterator, $initial = null) |
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721 | /** |
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722 | * Reduce the collection to a single value, starting from the last element |
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723 | * @param callable $iterator the reducer |
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724 | * @param mixed $initial the initial value |
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725 | * @return mixed the final value |
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726 | */ |
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727 | 1 | public function reduceRight(callable $iterator, $initial = null) |
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731 | } |
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732 |