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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| 22 | class Collection implements \Iterator, \ArrayAccess, \Countable |
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| 23 | { |
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| 24 | /** |
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| 25 | * @var array |
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| 26 | */ |
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| 27 | protected $list = []; |
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| 28 | |||
| 29 | /** |
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| 30 | * @var int |
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| 31 | */ |
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| 32 | protected $position = 0; |
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| 33 | |||
| 34 | /** |
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| 35 | * this is required for the unset() <=> offsetUnset() where an exception is |
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| 36 | * thrown if next() or rewind() is not called after unset. |
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| 37 | * @var bool |
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| 38 | */ |
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| 39 | protected $next_or_rewind_required = false; |
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| 40 | |||
| 41 | 87 | public function __construct() |
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| 45 | |||
| 46 | /** |
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| 47 | * @return int |
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| 48 | */ |
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| 49 | 12 | public function count() |
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| 53 | |||
| 54 | /** |
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| 55 | * This method is meant to be overridden by child Classes in order to throw |
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| 56 | * an Exception if the value can't be added, else it will be added normally. |
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| 57 | * |
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| 58 | * @param mixed $value |
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| 59 | */ |
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| 60 | 66 | protected function preAdd($value) |
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| 63 | |||
| 64 | /** |
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| 65 | * Get the next numeric offset. |
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| 66 | * |
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| 67 | * we get the MAX numeric offset we have and increment it by 1. |
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| 68 | */ |
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| 69 | 57 | protected function nextOffset() |
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| 80 | |||
| 81 | /** |
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| 82 | * @param string|int $offset |
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| 83 | * @param mixed $value |
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| 84 | * |
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| 85 | * @throws \Exception |
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| 86 | */ |
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| 87 | 72 | public function offsetSet($offset, $value) |
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| 96 | |||
| 97 | /** |
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| 98 | * This is not in the interface, add an item. |
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| 99 | * @return self |
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| 100 | * @throws \Exception |
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| 101 | */ |
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| 102 | 12 | public function add($item) |
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| 107 | |||
| 108 | /** |
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| 109 | * This is not in the interface, add an item passing it by reference. |
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| 110 | * |
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| 111 | * This will only accept variables as input. |
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| 112 | * |
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| 113 | * @return self |
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| 114 | * @throws \Exception |
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| 115 | */ |
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| 116 | 3 | public function addByReference(&$item) |
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| 122 | |||
| 123 | /** |
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| 124 | * @param string|int $offset |
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| 125 | * |
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| 126 | * @return mixed|null |
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| 127 | */ |
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| 128 | 21 | public function &offsetGet($offset) |
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| 129 | { |
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| 130 | 21 | if (array_key_exists($offset, $this->list)) { |
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| 131 | 18 | return $this->list[$offset]; |
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| 132 | } |
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| 133 | 3 | $null = null; |
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| 134 | 3 | return $null; |
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| 135 | } |
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| 136 | |||
| 137 | /** |
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| 138 | * @return bool |
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| 139 | */ |
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| 140 | 6 | public function offsetExists($offset) |
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| 144 | |||
| 145 | 12 | public function offsetUnset($offset) |
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| 156 | |||
| 157 | 18 | public function rewind() |
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| 162 | |||
| 163 | 9 | public function next() |
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| 168 | |||
| 169 | /** |
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| 170 | * This is not in the interface, go back in the array. |
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| 171 | */ |
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| 172 | 3 | public function prev() |
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| 173 | { |
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| 174 | 3 | --$this->position; |
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| 175 | 3 | $this->next_or_rewind_required = false; |
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| 176 | 3 | } |
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| 177 | |||
| 178 | /** |
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| 179 | * @return bool |
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| 180 | */ |
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| 181 | 12 | public function valid() |
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| 182 | { |
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| 183 | 12 | if (empty($this->list)) { |
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| 184 | 6 | return false; |
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| 185 | } |
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| 186 | 6 | return array_key_exists($this->position, array_keys($this->list)); |
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| 187 | } |
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| 188 | |||
| 189 | 21 | public function current() |
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| 190 | { |
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| 191 | 21 | if ($this->next_or_rewind_required) { |
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| 192 | 3 | throw new \Exception('Calling next or rewind is required after call to unset, current item can\'t be accessed otherwise because it is removed.'); |
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| 193 | } |
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| 194 | 18 | return $this->list[$this->key()]; |
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| 195 | } |
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| 196 | |||
| 197 | /** |
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| 198 | * @return string |
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| 199 | */ |
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| 200 | 18 | public function key() |
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| 206 | |||
| 207 | /** |
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| 208 | * @return int |
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| 209 | */ |
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| 210 | 3 | public function position() |
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| 214 | |||
| 215 | /** |
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| 216 | * This is not in the interface, Get the last item. |
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| 217 | */ |
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| 218 | 6 | public function last() |
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| 219 | { |
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| 220 | 6 | $keys = array_keys($this->list); |
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| 221 | 6 | $offset = array_pop($keys); |
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| 222 | 6 | if (array_key_exists($offset, $this->list)) { |
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| 223 | 3 | return $this->list[$offset]; |
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| 224 | } |
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| 225 | 3 | $null = null; |
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| 226 | 3 | return $null; |
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| 227 | } |
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| 228 | |||
| 229 | /** |
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| 230 | * This is not in the interface, Get the first item. |
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| 231 | */ |
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| 232 | 6 | public function first() |
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| 233 | { |
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| 234 | 6 | $keys = array_keys($this->list); |
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| 235 | 6 | $offset = array_shift($keys); |
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| 236 | 6 | if (array_key_exists($offset, $this->list)) { |
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| 237 | 3 | return $this->list[$offset]; |
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| 238 | } |
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| 239 | 3 | $null = null; |
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| 240 | 3 | return $null; |
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| 241 | } |
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| 242 | |||
| 243 | /** |
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| 244 | * This is not in the interface, Return the keys of the internal list. |
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| 245 | * |
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| 246 | * @return array |
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| 247 | */ |
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| 248 | 9 | public function keys() |
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| 249 | { |
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| 250 | 9 | return array_keys($this->list); |
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| 251 | } |
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| 252 | |||
| 253 | /** |
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| 254 | * This is not in the interface, cast the internal list to an array. |
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| 255 | * |
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| 256 | * @return array |
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| 257 | */ |
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| 258 | 24 | public function toArray() |
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| 262 | |||
| 263 | |||
| 264 | /** |
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| 265 | * This is not in the interface, merge this object with another object and act |
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| 266 | * like array_merge, numeric indexes are added, other indexes are overridden. |
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| 267 | * |
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| 268 | * This method will alter the current object. |
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| 269 | * |
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| 270 | * @param Collection $another_list |
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| 271 | * |
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| 272 | * @return self |
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| 273 | * |
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| 274 | * @throws \Exception |
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| 275 | * |
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| 276 | */ |
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| 277 | 3 | public function merge(Collection $another_list) |
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| 278 | { |
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| 279 | 3 | for ($another_list->rewind(); $another_list->valid(); $another_list->next()) { |
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| 280 | $key = $another_list->key(); |
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| 281 | try { |
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| 282 | $this->offsetSet(is_numeric($key) ? null : $key, $another_list->current()); |
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| 283 | } catch (\Exception $e) { |
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| 284 | throw $e; |
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| 285 | } |
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| 286 | } |
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| 287 | 3 | return $this; |
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| 288 | } |
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| 289 | |||
| 290 | /** |
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| 291 | * Change the position of item at $offset1 in the internal array to be at |
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| 292 | * the position of item at $offset2 and vise versa. |
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| 293 | * |
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| 294 | * @param $offset1 |
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| 295 | * @param $offset2 |
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| 296 | * |
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| 297 | * @return $this |
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| 298 | * @throws \Exception |
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| 299 | */ |
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| 300 | 9 | public function swap($offset1, $offset2) |
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| 301 | { |
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| 302 | 9 | $pos1 = $this->offsetPosition($offset1); |
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| 303 | 9 | $pos2 = $this->offsetPosition($offset2); |
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| 304 | 9 | if ($pos1 === false || $pos2 === false) { |
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| 305 | // offset does not exist |
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| 306 | 3 | throw new \Exception("Trying to swap non exist offsets"); |
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| 307 | } |
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| 308 | 6 | if ($pos1 == $pos2) { |
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| 309 | 3 | return $this; |
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| 310 | } |
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| 311 | 3 | $temp = $this[$offset1]; |
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| 312 | 3 | $this[$offset1] = $this[$offset2]; |
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| 313 | 3 | $this[$offset2] = $temp; |
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| 314 | |||
| 315 | 3 | return $this; |
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| 316 | } |
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| 317 | |||
| 318 | /** |
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| 319 | * Change the position of item at $offset1 in the internal array to be at |
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| 320 | * the position of item at $offset2 and vise versa using re-order and refilling |
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| 321 | * the array |
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| 322 | * |
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| 323 | * @param $offset1 |
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| 324 | * @param $offset2 |
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| 325 | * |
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| 326 | * @return self |
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| 327 | * |
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| 328 | * @throws \Exception |
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| 329 | */ |
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| 330 | 9 | public function swapReorder($offset1, $offset2) |
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| 331 | { |
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| 332 | 9 | $pos1 = $this->offsetPosition($offset1); |
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| 333 | 9 | $pos2 = $this->offsetPosition($offset2); |
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| 334 | 9 | if ($pos1 === false || $pos2 === false) { |
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| 335 | // offset does not exist |
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| 336 | 3 | throw new \Exception("Trying to swap non exist offsets"); |
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| 337 | } |
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| 338 | 6 | if ($pos1 == $pos2) { |
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| 339 | 3 | return $this; |
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| 340 | } |
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| 341 | |||
| 342 | 3 | $clone = clone $this; |
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| 343 | 3 | for ($clone->rewind(); $clone->valid(); $clone->next()) { |
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| 344 | 3 | $key = $clone->key(); |
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| 345 | 3 | $curr_pos = $clone->position(); |
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| 346 | 3 | if ($curr_pos === $pos1) { |
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| 347 | 3 | $this[$key] = $clone->offsetGet($offset2); |
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| 348 | 3 | } elseif ($curr_pos === $pos2) { |
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| 349 | 3 | $this[$key] = $clone->offsetGet($offset1); |
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| 350 | 1 | } else { |
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| 351 | 3 | $this[$key] = $clone->current(); |
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| 352 | } |
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| 353 | 1 | } |
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| 354 | |||
| 355 | 3 | return $this; |
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| 356 | } |
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| 357 | |||
| 358 | |||
| 359 | /** |
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| 360 | * Get the item by internal pointer numeric position and not by the offset. |
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| 361 | * |
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| 362 | * This is not in the interface. |
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| 363 | * |
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| 364 | * @param int $pos |
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| 365 | * |
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| 366 | * @return null|mixed |
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| 367 | */ |
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| 368 | 6 | public function byPositionGet($pos) |
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| 369 | { |
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| 370 | 6 | $keys = $this->keys(); |
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| 371 | 6 | if (array_key_exists($pos, $keys)) { |
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| 372 | 3 | $offset = $keys[$pos]; |
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| 373 | 3 | return $this->list[$offset]; |
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| 374 | } |
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| 375 | |||
| 376 | 3 | return null; |
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| 377 | } |
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| 378 | |||
| 379 | /** |
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| 380 | * Get the internal pointer numeric position which corresponds to the |
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| 381 | * offset passed. |
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| 382 | * this is not in the interface |
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| 383 | * |
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| 384 | * @param $offset |
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| 385 | * |
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| 386 | * @return int|FALSE |
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| 387 | */ |
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| 388 | 27 | public function offsetPosition($offset) |
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| 394 | |||
| 395 | /** |
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| 396 | * Check if this container is empty. |
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| 397 | * |
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| 398 | * This is not in the interface |
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| 399 | * @return bool |
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| 400 | */ |
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| 401 | 6 | public function isEmpty() |
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| 402 | { |
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| 403 | 6 | return count($this) === 0; |
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| 404 | } |
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| 405 | |||
| 406 | /** |
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| 407 | * Perform array_diff_key against another list where the first parameter is |
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| 408 | * this collection and the second is the new list. |
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| 409 | * |
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| 410 | * This will return a new Collection. |
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| 411 | * |
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| 412 | * @param Collection $another_list |
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| 413 | * |
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| 414 | * @return Collection |
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| 415 | */ |
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| 416 | 3 | public function diffKey(Collection $another_list) |
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| 425 | |||
| 426 | /** |
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| 427 | * A version of php array_diff_assoc which is recursive. |
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| 428 | * |
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| 429 | * array_diff_assoc — Computes the difference of arrays with additional index check |
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| 430 | * |
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| 431 | * @param array $array1 |
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| 432 | * @param array $array2 |
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| 433 | * |
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| 434 | * @return array |
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| 435 | */ |
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| 436 | 9 | protected static function arrayDiffRecursiveAssoc(array $array1, array $array2) |
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| 437 | { |
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| 438 | 9 | $ret = array(); |
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| 439 | |||
| 440 | 9 | foreach ($array1 as $key1 => $value1) { |
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| 441 | 9 | if (!array_key_exists($key1, $array2)) { |
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| 442 | 6 | $ret[$key1] = $value1; |
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| 443 | 6 | continue; |
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| 444 | } |
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| 445 | 3 | if (is_array($value1) && is_array($array2[$key1])) { |
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| 446 | $recursive_diff = self::arrayDiffRecursiveAssoc($value1, $array2[$key1]); |
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| 447 | if (count($recursive_diff)) { |
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| 448 | $ret[$key1] = $recursive_diff; |
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| 449 | } |
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| 450 | 3 | } elseif ($value1 instanceof Collection && $array2[$key1] instanceof Collection) { |
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| 451 | 3 | $recursive_diff = $value1->diffRecursiveAssoc($array2[$key1]); |
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| 452 | 3 | if ($recursive_diff->count()) { |
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| 453 | 2 | $ret[$key1] = $recursive_diff; |
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| 454 | } |
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| 455 | 3 | } elseif (!is_array($value1) && !is_array($array2[$key1])) { |
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| 456 | 3 | if ($value1 !== $array2[$key1]) { |
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| 457 | 2 | $ret[$key1] = $value1; |
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| 458 | } |
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| 459 | 1 | } else { |
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| 460 | 1 | $ret[$key1] = $value1; |
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| 461 | } |
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| 462 | 3 | } |
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| 463 | 9 | return $ret; |
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| 464 | } |
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| 465 | |||
| 466 | /** |
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| 467 | * Return Recursive diff from another list with index check. |
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| 468 | * |
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| 469 | * The first array is this collection and compute the diff against the passed collection. |
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| 470 | * |
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| 471 | * This will return a new Collection. |
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| 472 | * |
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| 473 | * @param Collection $another_list |
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| 474 | * |
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| 475 | * @return static |
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| 476 | */ |
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| 477 | 9 | public function diffRecursiveAssoc(Collection $another_list) |
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| 478 | { |
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| 479 | 9 | $ret = new static(); |
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| 480 | 9 | $diff = static::arrayDiffRecursiveAssoc($this->toArray(), $another_list->toArray()); |
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| 481 | 9 | foreach ($diff as $key => $value) { |
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| 482 | 6 | $ret[$key] = $value; |
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| 483 | 3 | } |
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| 484 | 9 | return $ret; |
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| 485 | } |
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| 486 | |||
| 487 | /** |
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| 488 | * A version of php array_diff which is recursive. |
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| 489 | * |
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| 490 | * array_diff — Computes the difference of arrays |
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| 491 | * |
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| 492 | * This function is costy because it uses array_search |
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| 493 | * |
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| 494 | * @param array $array1 |
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| 495 | * @param array $array2 |
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| 496 | * |
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| 497 | * @return array |
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| 498 | */ |
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| 499 | 3 | protected static function arrayDiffRecursive(array $array1, array $array2) |
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| 528 | |||
| 529 | /** |
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| 530 | * Return Recursive diff from another list. |
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| 531 | * |
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| 532 | * The first array is this collection and compute the diff against the passed collection. |
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| 533 | * |
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| 534 | * This will return a new Collection. |
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| 535 | * |
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| 536 | * @param Collection $another_list |
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| 537 | * |
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| 538 | * @return static |
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| 539 | */ |
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| 540 | 3 | public function diffRecursive(Collection $another_list) |
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| 549 | |||
| 550 | /** |
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| 551 | * Implementation of array_intesect_key against another list. |
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| 552 | * |
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| 553 | * This will return a new Collection. |
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| 554 | * |
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| 555 | * @param Collection $another_list |
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| 556 | * |
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| 557 | * @return static |
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| 558 | */ |
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| 559 | 3 | public function intersectKey(Collection $another_list) |
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| 569 | } |
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| 570 |
This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.