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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| 26 | class Collection implements ArrayAccess, Iterator, Countable, JsonSerializable |
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| 27 | { |
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| 28 | /** @var array */ |
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| 29 | protected $items; |
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| 30 | |||
| 31 | /** |
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| 32 | * Collection constructor. |
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| 33 | * |
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| 34 | * @param array $items |
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| 35 | */ |
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| 36 | 93 | public function __construct(array $items = []) |
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| 41 | |||
| 42 | /** |
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| 43 | * Generate a collection from an array of items. |
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| 44 | * I created this method so that it's possible to extend a collection more easily. |
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| 45 | * |
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| 46 | * @param mixed $items |
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| 47 | * |
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| 48 | * @return Collection |
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| 49 | */ |
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| 50 | 30 | public static function factory($items = null) |
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| 57 | |||
| 58 | /** |
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| 59 | * Get collection as an array |
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| 60 | * |
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| 61 | * @return array |
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| 62 | */ |
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| 63 | 47 | public function toArray() |
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| 67 | |||
| 68 | /** |
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| 69 | * Determine if collection has a given key |
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| 70 | * |
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| 71 | * @param mixed $key The key to look for |
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| 72 | * |
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| 73 | * @return bool |
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| 74 | */ |
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| 75 | 47 | public function has($key) |
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| 79 | |||
| 80 | /** |
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| 81 | * Does collection have item at position? |
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| 82 | * |
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| 83 | * Determine if collection has an item at a particular position (indexed from one). |
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| 84 | * Position can be positive and start from the beginning or it can be negative and |
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| 85 | * start from the end. |
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| 86 | * |
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| 87 | * @param int $position |
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| 88 | * |
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| 89 | * @return bool |
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| 90 | */ |
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| 91 | 2 | public function hasValueAt($position) |
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| 100 | |||
| 101 | /** |
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| 102 | * Get key at given position |
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| 103 | * |
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| 104 | * Returns the key at the given position, starting from one. Position can be positive (start from beginning) or |
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| 105 | * negative (start from the end). |
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| 106 | * |
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| 107 | * If the position does not exist, a RuntimeException is thrown. |
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| 108 | * |
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| 109 | * @param int $position |
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| 110 | * |
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| 111 | * @return string |
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| 112 | * |
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| 113 | * @throws RuntimeException |
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| 114 | */ |
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| 115 | 6 | public function getKeyAt($position) |
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| 129 | |||
| 130 | /** |
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| 131 | * Get value at given position |
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| 132 | * |
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| 133 | * Returns the value at the given position, starting from one. Position can be positive (start from beginning) or |
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| 134 | * negative (start from the end). |
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| 135 | * |
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| 136 | * If the position does not exist, a RuntimeException is thrown. |
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| 137 | * |
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| 138 | * @param int $position |
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| 139 | * |
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| 140 | * @return mixed |
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| 141 | * |
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| 142 | * @throws RuntimeException |
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| 143 | */ |
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| 144 | 2 | public function getValueAt($position) |
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| 148 | |||
| 149 | /** |
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| 150 | * Get the key of the first item found matching $item |
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| 151 | * |
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| 152 | * @todo should this throw an exception if not found? |
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| 153 | * |
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| 154 | * @param mixed|callable $item |
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| 155 | * |
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| 156 | * @return mixed|null |
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| 157 | */ |
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| 158 | 2 | public function keyOf($item) |
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| 173 | |||
| 174 | /** |
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| 175 | * Get the offset (index) of the first item found that matches $item |
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| 176 | * |
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| 177 | * @todo should this throw an exception if not found? |
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| 178 | * |
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| 179 | * @param mixed|callable $item |
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| 180 | * |
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| 181 | * @return int|null |
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| 182 | */ |
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| 183 | 2 | public function indexOf($item) |
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| 201 | |||
| 202 | /** |
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| 203 | * Get item by key, with an optional default return value |
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| 204 | * |
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| 205 | * @param mixed $key |
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| 206 | * @param mixed $default |
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| 207 | * |
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| 208 | * @return mixed |
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| 209 | */ |
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| 210 | 8 | public function get($key, $default = null) |
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| 218 | |||
| 219 | /** |
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| 220 | * Add an item with no regard to key |
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| 221 | * |
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| 222 | * @param mixed $value |
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| 223 | * |
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| 224 | * @return $this |
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| 225 | */ |
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| 226 | 8 | public function add($value) |
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| 232 | |||
| 233 | /** |
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| 234 | * Set an item at a given key |
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| 235 | * |
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| 236 | * @param mixed $key |
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| 237 | * @param mixed $value |
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| 238 | * @param bool $overwrite If false, do not overwrite existing key |
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| 239 | * |
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| 240 | * @return $this |
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| 241 | */ |
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| 242 | 14 | public function set($key, $value, $overwrite = true) |
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| 250 | |||
| 251 | /** |
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| 252 | * Delete an item by key |
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| 253 | * |
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| 254 | * @param mixed $key |
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| 255 | * |
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| 256 | * @return $this |
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| 257 | */ |
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| 258 | 3 | public function delete($key) |
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| 264 | |||
| 265 | /** |
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| 266 | * Clear the collection of all its items. |
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| 267 | * |
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| 268 | * @return $this |
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| 269 | */ |
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| 270 | 2 | public function clear() |
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| 276 | |||
| 277 | /** |
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| 278 | * Determine if collection contains given value |
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| 279 | * |
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| 280 | * @param mixed|callable $val |
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| 281 | * @param mixed $key |
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| 282 | * |
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| 283 | * @return bool |
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| 284 | */ |
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| 285 | 4 | public function contains($val, $key = null) |
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| 303 | |||
| 304 | /** |
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| 305 | * Fetch item from collection by key and remove it from collection |
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| 306 | * |
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| 307 | * @param mixed $key |
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| 308 | * |
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| 309 | * @return mixed |
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| 310 | */ |
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| 311 | 1 | public function pull($key) |
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| 319 | |||
| 320 | /** |
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| 321 | * Join collection items using a delimiter |
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| 322 | * |
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| 323 | * @param string $delim |
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| 324 | * |
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| 325 | * @return string |
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| 326 | */ |
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| 327 | 1 | public function join($delim = '') |
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| 331 | |||
| 332 | /** |
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| 333 | * Determine if collection has any items |
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| 334 | * |
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| 335 | * @return bool |
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| 336 | */ |
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| 337 | 4 | public function isEmpty() |
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| 341 | |||
| 342 | /** |
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| 343 | * Get a collection of only this collection's values (without its keys) |
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| 344 | * |
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| 345 | * @return Collection |
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| 346 | */ |
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| 347 | 1 | public function values() |
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| 351 | |||
| 352 | /** |
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| 353 | * Get a collection of only this collection's keys |
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| 354 | * |
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| 355 | * @return Collection |
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| 356 | */ |
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| 357 | 1 | public function keys() |
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| 361 | |||
| 362 | /** |
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| 363 | * Get a collection with order reversed |
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| 364 | * |
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| 365 | * @return Collection |
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| 366 | */ |
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| 367 | 6 | public function reverse() |
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| 371 | |||
| 372 | /** |
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| 373 | * Get a collection with keys and values flipped |
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| 374 | * |
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| 375 | * @return Collection |
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| 376 | */ |
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| 377 | 1 | public function flip() |
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| 385 | |||
| 386 | /** |
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| 387 | * Shuffle the order of this collection's values |
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| 388 | * |
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| 389 | * @return Collection |
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| 390 | */ |
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| 391 | 1 | public function shuffle() |
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| 396 | |||
| 397 | /** |
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| 398 | * Get a random value from the collection |
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| 399 | * |
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| 400 | * @todo might be useful to add a $count param to specify you want $count random items... |
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| 401 | * |
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| 402 | * @return mixed |
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| 403 | */ |
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| 404 | 1 | public function random() |
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| 408 | |||
| 409 | /** |
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| 410 | * Sort the collection (using values) |
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| 411 | * |
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| 412 | * @param callable $alg |
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| 413 | * |
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| 414 | * @return $this |
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| 415 | */ |
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| 416 | 2 | public function sort(callable $alg = null) |
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| 426 | |||
| 427 | /** |
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| 428 | * Sort the collection (using keys) |
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| 429 | * |
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| 430 | * @param callable $alg |
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| 431 | * |
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| 432 | * @return $this |
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| 433 | */ |
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| 434 | 2 | public function ksort(callable $alg = null) |
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| 444 | |||
| 445 | /** |
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| 446 | * Append items to collection without regard to keys |
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| 447 | * |
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| 448 | * @param array|Traversable $items |
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| 449 | * |
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| 450 | * @return $this |
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| 451 | */ |
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| 452 | 2 | public function append($items) |
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| 464 | |||
| 465 | /** |
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| 466 | * Return first item or first item where callback returns true |
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| 467 | * |
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| 468 | * @param callable|null $callback |
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| 469 | * |
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| 470 | * @return mixed|null |
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| 471 | */ |
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| 472 | 7 | public function first(callable $callback = null) |
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| 483 | |||
| 484 | /** |
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| 485 | * Return last item or last item where callback returns true |
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| 486 | * |
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| 487 | * @param callable|null $callback |
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| 488 | * |
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| 489 | * @return mixed|null |
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| 490 | */ |
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| 491 | 3 | public function last(callable $callback = null) |
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| 495 | |||
| 496 | /** |
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| 497 | * Map collection |
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| 498 | * |
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| 499 | * Create a new collection using the results of a callback function on each item in this collection. |
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| 500 | * |
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| 501 | * @param callable $callback |
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| 502 | * |
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| 503 | * @return Collection |
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| 504 | */ |
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| 505 | 3 | public function map(callable $callback) |
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| 516 | |||
| 517 | /** |
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| 518 | * Combine collection with another traversable/collection |
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| 519 | * |
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| 520 | * Using this collection's keys, and the incoming collection's values, a new collection is created and returned. |
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| 521 | * |
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| 522 | * @param array|Traversable $items |
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| 523 | * |
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| 524 | * @return Collection |
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| 525 | */ |
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| 526 | 5 | public function combine($items) |
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| 539 | |||
| 540 | /** |
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| 541 | * Get a new collection with only distinct values |
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| 542 | * |
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| 543 | * @return Collection |
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| 544 | */ |
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| 545 | 1 | public function distinct() |
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| 556 | |||
| 557 | /** |
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| 558 | * Remove all duplicate values from collection in-place |
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| 559 | * |
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| 560 | * @return Collection |
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| 561 | */ |
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| 562 | 1 | public function deduplicate() |
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| 568 | |||
| 569 | /** |
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| 570 | * Return a new collection with only filtered keys/values |
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| 571 | * |
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| 572 | * The callback accepts value, key, index and should return true if the item should be added to the returned |
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| 573 | * collection |
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| 574 | * |
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| 575 | * @param callable $callback |
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| 576 | * |
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| 577 | * @return Collection |
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| 578 | */ |
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| 579 | 2 | public function filter(callable $callback = null) |
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| 597 | |||
| 598 | /** |
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| 599 | * Fold collection into a single value |
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| 600 | * |
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| 601 | * Loop through collection calling a callback function and passing the result to the next iteration, eventually |
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| 602 | * returning a single value. |
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| 603 | * |
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| 604 | * @param callable $callback |
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| 605 | * @param mixed $initial |
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| 606 | * |
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| 607 | * @return null |
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| 608 | */ |
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| 609 | 1 | public function fold(callable $callback, $initial = null) |
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| 619 | |||
| 620 | /** |
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| 621 | * Return a merge of this collection and $items |
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| 622 | * |
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| 623 | * @param array|Traversable $items |
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| 624 | * |
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| 625 | * @return Collection |
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| 626 | */ |
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| 627 | 3 | public function merge($items) |
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| 640 | |||
| 641 | /** |
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| 642 | * Create a new collection with a union of this collection and $items |
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| 643 | * |
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| 644 | * This method is similar to merge, except that existing items will not be overwritten. |
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| 645 | * |
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| 646 | * @param $items |
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| 647 | */ |
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| 648 | 2 | public function union($items) |
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| 661 | |||
| 662 | /** |
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| 663 | * Call callback for each item in collection, passively |
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| 664 | * If at any point the callback returns false, iteration stops. |
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| 665 | * |
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| 666 | * @param callable $callback |
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| 667 | * |
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| 668 | * @return $this |
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| 669 | */ |
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| 670 | 2 | public function each(callable $callback) |
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| 681 | |||
| 682 | /** |
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| 683 | * Assert callback returns $expected value for each item in collection. |
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| 684 | * |
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| 685 | * @todo This can be used to easily make methods like all($callback) and none($callback). |
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| 686 | * |
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| 687 | * @param callable $callback |
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| 688 | * @param bool $expected |
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| 689 | * |
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| 690 | * @return bool |
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| 691 | */ |
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| 692 | 1 | public function assert(callable $callback, $expected = true) |
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| 703 | |||
| 704 | /** |
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| 705 | * Pipe collection through a callback |
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| 706 | * |
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| 707 | * @param callable $callback |
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| 708 | * |
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| 709 | * @return mixed |
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| 710 | */ |
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| 711 | 1 | public function pipe(callable $callback) |
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| 715 | |||
| 716 | /** |
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| 717 | * Get new collection in chunks of $size |
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| 718 | * |
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| 719 | * Creates a new collection of arrays of $size length. The remainder items will be placed at the end. |
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| 720 | * |
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| 721 | * @param int $size |
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| 722 | * |
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| 723 | * @return Collection |
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| 724 | */ |
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| 725 | 2 | public function chunk($size) |
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| 729 | |||
| 730 | /** |
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| 731 | * Get a new collection of $count chunks |
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| 732 | * |
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| 733 | * @todo It might be useful to have a method that spreads remainder items more evenly so you don't end up with the |
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| 734 | * last item containing only one or two items. |
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| 735 | * |
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| 736 | * @param int $count |
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| 737 | * |
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| 738 | * @return Collection |
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| 739 | */ |
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| 740 | 1 | public function split($count = 1) |
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| 744 | |||
| 745 | /** |
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| 746 | * Get a slice of this collection. |
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| 747 | * |
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| 748 | * @param int $offset |
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| 749 | * @param int|null $length |
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| 750 | * |
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| 751 | * @return Collection |
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| 752 | */ |
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| 753 | 1 | public function slice($offset, $length = null) |
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| 757 | |||
| 758 | /** |
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| 759 | * Get collection with only differing items |
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| 760 | * |
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| 761 | * @param array|Traversable $items |
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| 762 | * |
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| 763 | * @return Collection |
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| 764 | */ |
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| 765 | 1 | public function diff($items) |
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| 769 | |||
| 770 | /** |
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| 771 | * Get collection with only differing items (by key) |
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| 772 | * |
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| 773 | * @param array|Traversable $items |
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| 774 | * |
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| 775 | * @return Collection |
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| 776 | */ |
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| 777 | 1 | public function kdiff($items) |
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| 781 | |||
| 782 | /** |
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| 783 | * Get collection with only intersecting items |
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| 784 | * |
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| 785 | * @param array|Traversable $items |
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| 786 | * |
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| 787 | * @return Collection |
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| 788 | */ |
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| 789 | 1 | public function intersect($items) |
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| 793 | |||
| 794 | /** |
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| 795 | * Get collection with only intersecting items (by key) |
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| 796 | * |
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| 797 | * @param array|Traversable $items |
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| 798 | * |
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| 799 | * @return Collection |
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| 800 | */ |
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| 801 | 1 | public function kintersect($items) |
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| 805 | |||
| 806 | /** |
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| 807 | * Remove last item in collection and return it |
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| 808 | * |
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| 809 | * @return mixed |
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| 810 | */ |
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| 811 | 1 | public function pop() |
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| 815 | |||
| 816 | /** |
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| 817 | * Remove first item in collection and return it (and re-index if numerically indexed) |
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| 818 | * |
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| 819 | * @return mixed |
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| 820 | */ |
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| 821 | 2 | public function shift() |
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| 825 | |||
| 826 | /** |
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| 827 | * Add item to the end of the collection |
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| 828 | * |
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| 829 | * @note This method is no different than add() but I included it for consistency's sake since I have the others |
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| 830 | * |
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| 831 | * @param mixed $item |
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| 832 | * |
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| 833 | * @return $this |
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| 834 | */ |
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| 835 | 1 | public function push($item) |
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| 839 | |||
| 840 | /** |
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| 841 | * Add item to the beginning of the collection (and re-index if a numerically indexed collection) |
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| 842 | * |
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| 843 | * @param mixed $item |
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| 844 | * |
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| 845 | * @return $this |
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| 846 | */ |
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| 847 | 5 | public function unshift($item) |
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| 853 | |||
| 854 | /** |
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| 855 | * Get new collection padded to specified $size with $value |
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| 856 | * |
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| 857 | * Using $value, pad the collection to specified $size. If $size is smaller or equal to the size of the collection, |
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| 858 | * then no padding takes place. If $size is positive, padding is added to the end, while if negative, padding will |
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| 859 | * be added to the beginning. |
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| 860 | * |
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| 861 | * @param int $size |
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| 862 | * @param mixed $value |
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| 863 | * |
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| 864 | * @return Collection |
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| 865 | */ |
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| 866 | 3 | public function pad($size, $value = null) |
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| 879 | |||
| 880 | /** |
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| 881 | * Partition collection into two collections using a callback |
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| 882 | * |
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| 883 | * Iterates over each element in the collection with a callback. Items where callback returns true are placed in one |
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| 884 | * collection and the rest in another. Finally, the two collections are placed in an array and returned for easy use |
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| 885 | * with the list() function. ( list($a, $b) = $col->partition(function($val, $key, $index) {}) ) |
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| 886 | * |
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| 887 | * @param callable $callback |
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| 888 | * |
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| 889 | * @return array<Collection> |
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| 890 | */ |
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| 891 | 2 | public function partition(callable $callback) |
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| 907 | |||
| 908 | /** ++++ ++++ **/ |
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| 909 | /** ++ Interface Compliance ++ **/ |
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| 910 | /** ++++ ++++ **/ |
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| 911 | |||
| 912 | /** |
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| 913 | * @return array |
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| 914 | */ |
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| 915 | 1 | public function jsonSerialize() |
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| 919 | |||
| 920 | /** ++++ ++++ **/ |
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| 921 | /** ++ Array Access Methods ++ **/ |
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| 922 | /** ++++ ++++ **/ |
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| 923 | |||
| 924 | /** |
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| 925 | * {@inheritDoc} |
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| 926 | */ |
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| 927 | 1 | public function offsetExists($offset) |
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| 931 | |||
| 932 | /** |
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| 933 | * {@inheritDoc} |
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| 934 | */ |
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| 935 | 2 | public function offsetGet($offset) |
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| 943 | |||
| 944 | /** |
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| 945 | * {@inheritDoc} |
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| 946 | */ |
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| 947 | 1 | public function offsetUnset($offset) |
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| 951 | |||
| 952 | /** |
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| 953 | * {@inheritDoc} |
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| 954 | */ |
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| 955 | 1 | public function offsetSet($offset, $value) |
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| 963 | |||
| 964 | /** ++++ ++++ **/ |
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| 965 | /** ++ Iterator Methods ++ **/ |
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| 966 | /** ++++ ++++ **/ |
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| 967 | |||
| 968 | /** |
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| 969 | * {@inheritDoc} |
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| 970 | */ |
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| 971 | 35 | public function current() |
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| 975 | |||
| 976 | /** |
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| 977 | * {@inheritDoc} |
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| 978 | */ |
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| 979 | 35 | public function key() |
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| 983 | |||
| 984 | /** |
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| 985 | * {@inheritDoc} |
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| 986 | */ |
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| 987 | 34 | public function next() |
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| 991 | |||
| 992 | /** |
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| 993 | * {@inheritDoc} |
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| 994 | * |
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| 995 | * @todo Should this return $this? |
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| 996 | */ |
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| 997 | 93 | public function rewind() |
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| 1001 | |||
| 1002 | /** |
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| 1003 | * {@inheritDoc} |
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| 1004 | */ |
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| 1005 | 36 | public function valid() |
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| 1009 | |||
| 1010 | /** ++++ ++++ **/ |
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| 1011 | /** ++ Countable Method ++ **/ |
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| 1012 | /** ++++ ++++ **/ |
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| 1013 | |||
| 1014 | /** |
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| 1015 | * {@inheritDoc} |
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| 1016 | */ |
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| 1017 | 10 | public function count() |
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| 1021 | } |