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 $iterator = null; |
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| 10 | |||
| 11 | 4 | protected static function rangeGenerator($low, $high, $step = 1) |
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| 18 | /** |
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| 19 | * Create a collection based on a range generator |
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| 20 | * @param int|float $low start value |
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| 21 | * @param int|float $high end value |
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| 22 | * @param int|float $step increment |
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| 23 | * @return Collection |
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| 24 | */ |
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| 25 | 4 | public static function range($low, $high, $step = 1) : Collection |
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| 29 | /** |
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| 30 | * A static alias of the __constructor |
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| 31 | * @param mixed $input Anything iterable |
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| 32 | * @return Collection |
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| 33 | */ |
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| 34 | 50 | public static function from($input) : Collection |
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| 38 | /** |
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| 39 | * Create an instance |
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| 40 | * @param mixed $input Anything iterable |
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| 41 | */ |
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| 42 | 54 | public function __construct($input = []) |
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| 75 | |||
| 76 | /** |
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| 77 | * Applies all pending operations |
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| 78 | * @return $this |
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| 79 | */ |
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| 80 | 45 | public function squash() : Collection |
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| 87 | /** |
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| 88 | * Get an actual array from the collection |
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| 89 | * @return array |
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| 90 | */ |
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| 91 | 43 | public function toArray() : array |
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| 96 | /** |
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| 97 | * Gets the first value in the collection or null if empty |
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| 98 | * @return mixed |
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| 99 | */ |
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| 100 | 3 | public function value() |
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| 107 | |||
| 108 | // iterator |
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| 109 | 51 | public function key() |
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| 157 | |||
| 158 | // array access |
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| 159 | 1 | public function offsetGet($offset) |
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| 175 | /** |
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| 176 | * Get the collection length |
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| 177 | * @return int |
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| 178 | */ |
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| 179 | 1 | public function count() |
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| 184 | |||
| 185 | // mutators |
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| 186 | /** |
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| 187 | * Filter values from the collection based on a predicate. The callback will receive the value, key and collection |
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| 188 | * @param callable $iterator the predicate |
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| 189 | * @return $this |
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| 190 | */ |
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| 191 | 8 | public function filter(callable $iterator) : Collection |
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| 196 | /** |
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| 197 | * Pass all values of the collection through a mutator callable, which will receive the value, key and collection |
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| 198 | * @param callable $iterator the mutator |
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| 199 | * @return $this |
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| 200 | */ |
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| 201 | 4 | public function map(callable $iterator) : Collection |
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| 206 | /** |
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| 207 | * Clone the current collection and return it. |
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| 208 | * @return Collection |
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| 209 | */ |
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| 210 | public function clone() : Collection |
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| 214 | /** |
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| 215 | * Remove all falsy values from the collection (uses filter internally). |
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| 216 | * @return $this |
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| 217 | */ |
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| 218 | 1 | public function compact() : Collection |
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| 224 | /** |
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| 225 | * Exclude all listed values from the collection (uses filter internally). |
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| 226 | * @param iterable $values the values to exclude |
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| 227 | * @return $this |
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| 228 | */ |
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| 229 | 3 | public function difference($values) : Collection |
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| 242 | /** |
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| 243 | * Append more values to the collection |
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| 244 | * @param iterable $source the values to add |
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| 245 | * @return Collection |
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| 246 | */ |
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| 247 | 2 | public function extend($source) : Collection |
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| 254 | /** |
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| 255 | * Append more values to the collection |
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| 256 | * @param iterable $source the values to add |
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| 257 | * @return Collection |
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| 258 | */ |
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| 259 | 1 | public function merge($source) : Collection |
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| 263 | /** |
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| 264 | * Perform a shallow flatten of the collection |
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| 265 | * @return Collection |
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| 266 | */ |
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| 267 | 1 | public function flatten() : Collection |
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| 276 | /** |
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| 277 | * Group by a key (if a callable is used - return the value to group by) |
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| 278 | * @param string|callable $iterator the key to group by |
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| 279 | * @return Collection |
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| 280 | */ |
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| 281 | 1 | public function groupBy($iterator) : Collection |
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| 290 | /** |
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| 291 | * Get the first X items from the collection |
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| 292 | * @param int $count the number of items to include (defaults to 1) |
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| 293 | * @return Collection |
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| 294 | */ |
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| 295 | 1 | public function first(int $count = 1) : Collection |
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| 307 | /** |
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| 308 | * Get the first X items from the collection |
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| 309 | * @param int $count the number of items to include (defaults to 1) |
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| 310 | * @return Collection |
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| 311 | */ |
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| 312 | 1 | public function head(int $count = 1) : Collection |
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| 316 | /** |
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| 317 | * Get the last X items from the collection |
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| 318 | * @param int $count the number of items to include (defaults to 1) |
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| 319 | * @return Collection |
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| 320 | */ |
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| 321 | 2 | public function last(int $count = 1) : Collection |
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| 326 | /** |
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| 327 | * Get the first X items from the collection |
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| 328 | * @param int $count the number of items to include (defaults to 1) |
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| 329 | * @return Collection |
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| 330 | */ |
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| 331 | 1 | public function tail(int $count = 1) : Collection |
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| 335 | /** |
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| 336 | * Get all but the last X items from the collection |
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| 337 | * @param int $count the number of items to exclude (defaults to 1) |
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| 338 | * @return Collection |
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| 339 | */ |
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| 340 | 1 | public function initial(int $count = 1) : Collection |
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| 345 | /** |
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| 346 | * Get all but the first X items from the collection |
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| 347 | * @param int $count the number of items to exclude (defaults to 1) |
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| 348 | * @return Collection |
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| 349 | */ |
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| 350 | 1 | public function rest(int $count = 1) : Collection |
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| 355 | /** |
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| 356 | * Execute a callable for each item in the collection (does not modify the collection) |
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| 357 | * @param callable $iterator the callable to execute |
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| 358 | * @return $this |
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| 359 | */ |
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| 360 | 1 | public function each(callable $iterator) : Collection |
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| 367 | /** |
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| 368 | * Execute a callable for each item in the collection (does not modify the collection) |
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| 369 | * @param callable $iterator the callable to execute |
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| 370 | * @return $this |
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| 371 | */ |
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| 372 | 1 | public function invoke(callable $iterator) : Collection |
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| 376 | /** |
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| 377 | * Get all the collection keys |
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| 378 | * @return $this |
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| 379 | */ |
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| 380 | public function keys() : Collection |
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| 384 | /** |
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| 385 | * Pluck a value from each object (uses map internally) |
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| 386 | * @param string|int $key the key to extract |
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| 387 | * @return $this |
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| 388 | */ |
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| 389 | 1 | public function pluck($key) : Collection |
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| 397 | /** |
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| 398 | * Intersect the collection with another iterable (uses filter internally) |
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| 399 | * @param interable $values the data to intersect with |
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| 400 | * @return $this |
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| 401 | */ |
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| 402 | 1 | public function intersection($values) : Collection |
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| 415 | /** |
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| 416 | * Reject values on a given predicate (opposite of filter) |
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| 417 | * @param callable $iterator the predicate |
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| 418 | * @return $this |
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| 419 | */ |
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| 420 | 1 | public function reject(callable $iterator) : Collection |
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| 426 | /** |
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| 427 | * Shuffle the values in the collection |
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| 428 | * @return Collection |
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| 429 | */ |
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| 430 | 1 | public function shuffle() : Collection |
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| 441 | /** |
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| 442 | * Sort the collection using a standard sorting function |
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| 443 | * @param callable $iterator the sort function (must return -1, 0 or 1) |
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| 444 | * @return Collection |
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| 445 | */ |
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| 446 | 1 | public function sortBy(callable $iterator) : Collection |
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| 452 | /** |
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| 453 | * Inspect the whole collection (as an array) mid-chain |
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| 454 | * @param callable $iterator the callable to execute |
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| 455 | * @return $this |
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| 456 | */ |
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| 457 | 1 | public function tap(callable $iterator) : Collection |
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| 462 | /** |
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| 463 | * Modify the whole collection (as an array) mid-chain |
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| 464 | * @param callable $iterator the callable to execute |
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| 465 | * @return Collection |
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| 466 | */ |
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| 467 | 1 | public function thru(callable $iterator) : Collection |
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| 473 | /** |
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| 474 | * Leave only unique items in the collection |
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| 475 | * @return Collection |
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| 476 | */ |
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| 477 | 3 | public function unique() : Collection |
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| 488 | /** |
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| 489 | * Get only the values of the collection |
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| 490 | * @return Collection |
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| 491 | */ |
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| 492 | 3 | public function values() : Collection |
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| 496 | /** |
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| 497 | * Filter items from the collection using key => value pairs |
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| 498 | * @param array $properties the key => value to check for in each item |
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| 499 | * @param boolean $strict should the comparison be strict |
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| 500 | * @return $this |
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| 501 | */ |
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| 502 | public function where(array $properties, $strict = true) : Collection |
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| 514 | /** |
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| 515 | * Exclude all listed values from the collection (uses filter internally). |
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| 516 | * @param iterable $values the values to exclude |
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| 517 | * @return $this |
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| 518 | */ |
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| 519 | 2 | public function without($values) : Collection |
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| 523 | /** |
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| 524 | * Combine all the values from the collection with a key |
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| 525 | * @param iterable $keys the keys to use |
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| 526 | * @return Collection |
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| 527 | */ |
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| 528 | 2 | public function zip($keys) : Collection |
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| 535 | /** |
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| 536 | * Reverse the collection order |
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| 537 | * @return Collection |
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| 538 | */ |
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| 539 | 1 | public function reverse() : Collection |
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| 543 | |||
| 544 | // accessors |
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| 545 | /** |
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| 546 | * Do all of the items in the collection match a given criteria |
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| 547 | * @param callable $iterator the criteria - should return true / false |
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| 548 | * @return bool |
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| 549 | */ |
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| 550 | 1 | public function all(callable $iterator) : bool |
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| 559 | /** |
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| 560 | * Do any of the items in the collection match a given criteria |
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| 561 | * @param callable $iterator the criteria - should return true / false |
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| 562 | * @return bool |
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| 563 | */ |
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| 564 | 1 | public function any(callable $iterator) : bool |
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| 573 | /** |
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| 574 | * Does the collection contain a given value |
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| 575 | * @param mixed $needle the value to check for |
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| 576 | * @return bool |
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| 577 | */ |
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| 578 | 1 | public function contains($needle) : bool |
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| 587 | /** |
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| 588 | * Get the first element matching a given criteria (or null) |
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| 589 | * @param callable $iterator the filter criteria |
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| 590 | * @return mixed |
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| 591 | */ |
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| 592 | 1 | public function find(callable $iterator) |
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| 601 | /** |
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| 602 | * Get all the elements matching a given criteria (with the option to limit the number of results) |
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| 603 | * @param callable $iterator the search criteria |
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| 604 | * @param int|null $limit optional limit to the number of results (default to null - no limit) |
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| 605 | * @return Collection |
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| 606 | */ |
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| 607 | 1 | public function findAll(callable $iterator, int $limit = null) : Collection |
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| 620 | /** |
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| 621 | * Get the key corresponding to a value (or false) |
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| 622 | * @param mixed $needle the value to search for |
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| 623 | * @return mixed |
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| 624 | */ |
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| 625 | 1 | public function indexOf($needle) |
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| 629 | /** |
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| 630 | * Get the last key corresponding to a value (or false) |
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| 631 | * @param mixed $needle the value to search for |
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| 632 | * @return mixed |
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| 633 | */ |
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| 634 | 1 | public function lastIndexOf($needle) |
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| 644 | /** |
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| 645 | * Get the number of elements in the collection |
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| 646 | * @return int |
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| 647 | */ |
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| 648 | 1 | public function size() : int |
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| 652 | /** |
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| 653 | * Get the minimal item in the collection |
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| 654 | * @return mixed |
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| 655 | */ |
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| 656 | 1 | public function min() |
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| 668 | /** |
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| 669 | * Get the maximum item in the collection |
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| 670 | * @return mixed |
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| 671 | */ |
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| 672 | 1 | public function max() |
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| 684 | /** |
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| 685 | * Does the collection contain a given key |
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| 686 | * @param string|int $key the key to check |
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| 687 | * @return bool |
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| 688 | */ |
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| 689 | 1 | public function has($key) : bool |
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| 693 | /** |
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| 694 | * Reduce the collection to a single value |
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| 695 | * @param callable $iterator the reducer |
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| 696 | * @param mixed $initial the initial value |
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| 697 | * @return mixed the final value |
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| 698 | */ |
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| 699 | 1 | public function reduce(callable $iterator, $initial = null) |
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| 703 | /** |
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| 704 | * Reduce the collection to a single value, starting from the last element |
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| 705 | * @param callable $iterator the reducer |
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| 706 | * @param mixed $initial the initial value |
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| 707 | * @return mixed the final value |
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| 708 | */ |
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| 709 | 1 | public function reduceRight(callable $iterator, $initial = null) |
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| 713 | } |
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| 714 |