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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| 16 | class Collection implements CollectionContract { |
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| 17 | |||
| 18 | /** |
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| 19 | * Collection elements. |
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| 20 | * |
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| 21 | * @var array |
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| 22 | */ |
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| 23 | protected $elements = array(); |
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| 24 | |||
| 25 | /** |
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| 26 | * Collection type to enforce. |
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| 27 | * |
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| 28 | * @var Type |
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| 29 | */ |
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| 30 | private $type; |
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| 31 | |||
| 32 | /** |
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| 33 | * Where Collection is in loop. |
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| 34 | * |
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| 35 | * @var int |
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| 36 | */ |
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| 37 | protected $position = 0; |
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| 38 | |||
| 39 | /** |
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| 40 | * Collection constructor. |
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| 41 | * |
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| 42 | * @param string $type |
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| 43 | * @param array $elements |
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| 44 | */ |
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| 45 | 57 | public function __construct( $type, array $elements = array() ) { |
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| 62 | |||
| 63 | /** |
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| 64 | * {@inheritdoc} |
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| 65 | * |
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| 66 | * @return string |
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| 67 | */ |
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| 68 | 12 | public function get_type() { |
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| 71 | |||
| 72 | /** |
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| 73 | * {@inheritdoc} |
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| 74 | * |
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| 75 | * @param mixed $element |
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| 76 | * |
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| 77 | * @return Collection |
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| 78 | * |
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| 79 | * @throws InvalidArgumentException |
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| 80 | */ |
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| 81 | 12 | public function add( $element ) { |
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| 96 | |||
| 97 | /** |
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| 98 | * {@inheritdoc} |
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| 99 | * |
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| 100 | * @return Collection |
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| 101 | */ |
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| 102 | public function clear() { |
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| 105 | |||
| 106 | /** |
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| 107 | * {@inheritdoc} |
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| 108 | * |
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| 109 | * @param callable $condition Condition to satisfy. |
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| 110 | * |
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| 111 | * @return bool |
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| 112 | */ |
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| 113 | public function contains( $condition ) { |
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| 116 | |||
| 117 | /** |
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| 118 | * {@inheritdoc} |
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| 119 | * |
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| 120 | * @param callable $condition Condition to satisfy. |
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| 121 | * |
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| 122 | * @return mixed |
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| 123 | */ |
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| 124 | public function find( $condition ) { |
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| 129 | |||
| 130 | /** |
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| 131 | * {@inheritdoc} |
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| 132 | * |
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| 133 | * @param callable $condition Condition to satisfy. |
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| 134 | * |
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| 135 | * @return int |
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| 136 | */ |
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| 137 | public function find_index( $condition ) { |
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| 149 | |||
| 150 | /** |
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| 151 | * Fetches the element at the provided index. |
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| 152 | * |
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| 153 | * @param int $index Index to get element from. |
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| 154 | * |
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| 155 | * @return mixed |
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| 156 | * |
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| 157 | * @throws OutOfRangeException |
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| 158 | */ |
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| 159 | 12 | public function at( $index ) { |
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| 164 | |||
| 165 | /** |
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| 166 | * {@inheritdoc} |
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| 167 | * |
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| 168 | * @param int $index Index to check for existence. |
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| 169 | * |
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| 170 | * @return bool |
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| 171 | * |
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| 172 | * @throws InvalidArgumentException |
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| 173 | */ |
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| 174 | 12 | public function index_exists( $index ) { |
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| 185 | |||
| 186 | /** |
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| 187 | * {@inheritdoc} |
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| 188 | * |
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| 189 | * @param callable $condition Condition to satisfy. |
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| 190 | * |
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| 191 | * @return mixed |
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| 192 | */ |
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| 193 | public function filter( $condition ) { |
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| 204 | /** |
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| 205 | * {@inheritdoc} |
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| 206 | * |
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| 207 | * @param callable $condition Condition to satisfy. |
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| 208 | * |
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| 209 | * @return mixed |
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| 210 | */ |
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| 211 | public function find_last( $condition ) { |
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| 216 | |||
| 217 | /** |
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| 218 | * {@inheritdoc} |
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| 219 | * |
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| 220 | * @param callable $condition |
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| 221 | * @return int |
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| 222 | */ |
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| 223 | public function find_last_index( $condition ) { |
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| 235 | |||
| 236 | /** |
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| 237 | * {@inheritdoc} |
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| 238 | * |
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| 239 | * @param int $start Begining index to slice from. |
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| 240 | * @param int $end End index to slice to. |
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| 241 | * |
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| 242 | * @return Collection |
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| 243 | * |
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| 244 | * @throws InvalidArgumentException |
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| 245 | */ |
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| 246 | public function slice( $start, $end ) { |
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| 267 | |||
| 268 | /** |
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| 269 | * {@inheritdoc} |
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| 270 | * |
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| 271 | * @param int $index Index to start at. |
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| 272 | * @param mixed $element Element to insert. |
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| 273 | * |
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| 274 | * @return Collection |
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| 275 | * |
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| 276 | * @throws InvalidArgumentException |
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| 277 | * @throws OutOfRangeException |
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| 278 | */ |
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| 279 | public function insert( $index, $element ) { |
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| 290 | |||
| 291 | /** |
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| 292 | * {@inheritdoc} |
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| 293 | * |
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| 294 | * @param int $index Index to start insertion at. |
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| 295 | * @param array $elements Elements in insert. |
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| 296 | * |
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| 297 | * @return Collection |
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| 298 | * |
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| 299 | * @throws OutOfRangeException |
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| 300 | */ |
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| 301 | public function insert_range( $index, array $elements ) { |
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| 317 | |||
| 318 | /** |
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| 319 | * {@inheritdoc} |
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| 320 | * |
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| 321 | * @param callable $condition Condition to satisfy. |
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| 322 | * |
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| 323 | * @return Collection |
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| 324 | */ |
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| 325 | public function without( $condition ) { |
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| 332 | |||
| 333 | /** |
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| 334 | * {@inheritdoc} |
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| 335 | * |
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| 336 | * @param int $index Index to remove. |
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| 337 | * |
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| 338 | * @return Collection |
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| 339 | * |
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| 340 | * @throws OutOfRangeException |
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| 341 | */ |
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| 342 | public function remove_at( $index ) { |
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| 354 | /** |
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| 355 | * {@inheritdoc} |
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| 356 | * |
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| 357 | * @return Collection |
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| 358 | */ |
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| 359 | public function reverse() { |
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| 364 | |||
| 365 | /** |
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| 366 | * {@inheritdoc} |
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| 367 | * |
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| 368 | * @param callable $callback Sort callback. |
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| 369 | * |
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| 370 | * @return Collection |
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| 371 | */ |
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| 372 | public function sort( $callback ) { |
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| 377 | |||
| 378 | /** |
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| 379 | * {@inheritdoc} |
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| 380 | * |
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| 381 | * @return array |
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| 382 | */ |
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| 383 | 9 | public function to_array() { |
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| 386 | |||
| 387 | /** |
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| 388 | * {@inheritdoc} |
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| 389 | * |
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| 390 | * @param callable $callable Reducer function. |
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| 391 | * |
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| 392 | * @param null $initial Initial reducer value. |
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| 393 | * |
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| 394 | * @return mixed |
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| 395 | */ |
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| 396 | public function reduce( $callable, $initial = null ) { |
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| 399 | |||
| 400 | /** |
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| 401 | * {@inheritdoc} |
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| 402 | * |
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| 403 | * @param callable $condition Condition callback. |
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| 404 | * |
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| 405 | * @return bool |
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| 406 | */ |
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| 407 | public function every( $condition ) { |
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| 421 | |||
| 422 | /** |
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| 423 | * {@inheritdoc} |
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| 424 | * |
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| 425 | * @param int $num Number of elements to drop. |
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| 426 | * |
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| 427 | * @return Collection |
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| 428 | * |
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| 429 | * @throws InvalidArgumentException |
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| 430 | */ |
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| 431 | public function drop( $num ) { |
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| 434 | |||
| 435 | /** |
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| 436 | * {@inheritdoc} |
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| 437 | * |
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| 438 | * @param int $num Number of elements to drop. |
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| 439 | * |
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| 440 | * @return Collection |
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| 441 | * |
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| 442 | * @throws InvalidArgumentException |
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| 443 | */ |
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| 444 | public function drop_right( $num ) { |
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| 449 | |||
| 450 | /** |
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| 451 | * {@inheritdoc} |
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| 452 | * |
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| 453 | * @param callable $condition Condition callback. |
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| 454 | * |
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| 455 | * @return Collection |
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| 456 | */ |
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| 457 | public function drop_while( $condition ) { |
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| 461 | /** |
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| 462 | * {@inheritdoc} |
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| 463 | * |
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| 464 | * @return Collection |
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| 465 | * |
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| 466 | * @throws InvalidArgumentException |
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| 467 | */ |
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| 468 | public function tail() { |
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| 471 | |||
| 472 | /** |
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| 473 | * {@inheritdoc} |
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| 474 | * |
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| 475 | * @param int $num Number of elements to take. |
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| 476 | * |
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| 477 | * @return Collection |
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| 478 | * |
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| 479 | * @throws InvalidArgumentException |
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| 480 | */ |
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| 481 | public function take( $num ) { |
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| 484 | |||
| 485 | /** |
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| 486 | * {@inheritdoc} |
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| 487 | * |
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| 488 | * @param int $num Number of elements to take. |
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| 489 | * |
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| 490 | * @return Collection |
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| 491 | * |
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| 492 | * @throws InvalidArgumentException |
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| 493 | */ |
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| 494 | public function take_right( $num ) { |
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| 497 | |||
| 498 | /** |
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| 499 | * {@inheritdoc} |
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| 500 | * |
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| 501 | * @param callable $condition Callback function. |
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| 502 | * |
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| 503 | * @return Collection |
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| 504 | */ |
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| 505 | public function take_while( $condition ) { |
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| 510 | |||
| 511 | /** |
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| 512 | * {@inheritdoc} |
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| 513 | * |
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| 514 | * @param callable $callable Callback function. |
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| 515 | */ |
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| 516 | public function each( $callable ) { |
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| 521 | |||
| 522 | /** |
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| 523 | * {@inheritdoc} |
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| 524 | * |
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| 525 | * @param callable $callable Callback function. |
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| 526 | * |
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| 527 | * @return Collection |
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| 528 | */ |
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| 529 | 9 | public function map( $callable ) { |
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| 548 | |||
| 549 | /** |
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| 550 | * {@inheritdoc} |
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| 551 | * |
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| 552 | * @param callable $callable Reducer function. |
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| 553 | * @param null $initial Initial value. |
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| 554 | * |
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| 555 | * @return mixed |
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| 556 | */ |
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| 557 | public function reduce_right( $callable, $initial = null ) { |
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| 564 | |||
| 565 | /** |
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| 566 | * {@inheritdoc} |
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| 567 | * |
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| 568 | * @return Collection |
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| 569 | */ |
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| 570 | public function shuffle() { |
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| 576 | |||
| 577 | /** |
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| 578 | * {@inheritdoc} |
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| 579 | * |
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| 580 | * @param array|Collection $elements Array of elements to merge. |
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| 581 | * |
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| 582 | * @return Collection |
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| 583 | * |
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| 584 | * @throws InvalidArgumentException |
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| 585 | */ |
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| 586 | public function merge( $elements ) { |
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| 601 | |||
| 602 | /** |
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| 603 | * {@inheritdoc} |
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| 604 | * |
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| 605 | * @return mixed |
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| 606 | * |
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| 607 | * @throws OutOfBoundsException |
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| 608 | */ |
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| 609 | public function first() { |
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| 616 | |||
| 617 | /** |
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| 618 | * {@inheritdoc} |
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| 619 | * |
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| 620 | * @return mixed |
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| 621 | * |
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| 622 | * @throws OutOfBoundsException |
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| 623 | */ |
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| 624 | public function last() { |
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| 631 | |||
| 632 | /** |
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| 633 | * {@inheritdoc} |
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| 634 | * |
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| 635 | * @return int |
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| 636 | */ |
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| 637 | 18 | public function count() { |
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| 640 | |||
| 641 | /** |
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| 642 | * {@inheritDoc} |
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| 643 | * |
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| 644 | * @return array |
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| 645 | */ |
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| 646 | public function serialize() { |
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| 655 | |||
| 656 | /** |
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| 657 | * Return the current element. |
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| 658 | * |
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| 659 | * @return mixed |
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| 660 | */ |
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| 661 | 3 | public function current() { |
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| 664 | |||
| 665 | /** |
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| 666 | * Move forward to next element. |
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| 667 | */ |
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| 668 | 3 | public function next() { |
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| 671 | |||
| 672 | /** |
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| 673 | * Return the key of the current element. |
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| 674 | * |
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| 675 | * @return mixed |
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| 676 | */ |
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| 677 | 3 | public function key() { |
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| 680 | |||
| 681 | /** |
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| 682 | * Checks if current position is valid. |
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| 683 | * |
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| 684 | * @return bool |
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| 685 | */ |
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| 686 | 3 | public function valid() { |
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| 689 | |||
| 690 | /** |
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| 691 | * Rewind the Iterator to the first element. |
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| 692 | */ |
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| 693 | 3 | public function rewind() { |
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| 696 | |||
| 697 | /** |
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| 698 | * Creates a new instance of the Collection |
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| 699 | * from a trusted set of elements. |
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| 700 | * |
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| 701 | * @param array $elements Array of elements to pass into new collection. |
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| 702 | * @param null|mixed $type |
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| 703 | * |
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| 704 | * @return static |
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| 705 | */ |
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| 706 | 9 | protected function new_from_trusted( array $elements, $type = null ) { |
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| 712 | |||
| 713 | /** |
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| 714 | * Sets the elements without validating them. |
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| 715 | * |
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| 716 | * @param array $elements Pre-validated elements to set. |
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| 717 | */ |
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| 718 | 18 | protected function set_from_trusted( array $elements ) { |
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| 721 | |||
| 722 | /** |
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| 723 | * Number of elements true for the condition. |
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| 724 | * |
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| 725 | * @param callable $condition Condition to check. |
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| 726 | * @return int |
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| 727 | */ |
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| 728 | protected function count_while_true( $condition ) { |
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| 740 | |||
| 741 | /** |
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| 742 | * Validates a number to be used as an index. |
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| 743 | * |
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| 744 | * @param integer $index The number to be validated as an index. |
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| 745 | * |
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| 746 | * @throws OutOfRangeException |
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| 747 | */ |
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| 748 | 12 | protected function validate_index( $index ) { |
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| 755 | } |
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| 756 |