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<?php |
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|
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declare(strict_types=1); |
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|
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namespace AcyMailing\Libraries\Pelago\Emogrifier\Utilities; |
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|
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/** |
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* When computing many array intersections using the same array, it is more efficient to use `array_flip()` first and |
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* then `array_intersect_key()`, than `array_intersect()`. See the discussion at |
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* {@link https://stackoverflow.com/questions/6329211/php-array-intersect-efficiency Stack Overflow} for more |
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* information. |
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* |
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* Of course, this is only possible if the arrays contain integer or string values, and either don't contain duplicates, |
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* or that fact that duplicates will be removed does not matter. |
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* |
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* This class takes care of the detail. |
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* |
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* @internal |
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*/ |
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final class ArrayIntersector |
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{ |
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/** |
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* the array with which the object was constructed, with all its keys exchanged with their associated values |
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* |
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* @var array<array-key, array-key> |
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*/ |
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private $invertedArray; |
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|
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/** |
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* Constructs the object with the array that will be reused for many intersection computations. |
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* |
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* @param array<array-key, array-key> $array |
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*/ |
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public function __construct(array $array) |
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{ |
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$this->invertedArray = \array_flip($array); |
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} |
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|
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/** |
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* Computes the intersection of `$array` and the array with which this object was constructed. |
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* |
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* @param array<array-key, array-key> $array |
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* |
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* @return array<array-key, array-key> |
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* Returns an array containing all of the values in `$array` whose values exist in the array |
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* with which this object was constructed. Note that keys are preserved, order is maintained, but |
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* duplicates are removed. |
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*/ |
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public function intersectWith(array $array): array |
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{ |
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$invertedArray = \array_flip($array); |
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|
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$invertedIntersection = \array_intersect_key($invertedArray, $this->invertedArray); |
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|
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return \array_flip($invertedIntersection); |
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} |
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} |
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