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Shuffle associative array while preserving keys (Fisher–Yates shuffle algorithm)
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| <?php | |
| function fisherYatesShuffleAssoc(&$items, $seed) | |
| { | |
| $di = $items; | |
| @mt_srand($seed); | |
| $items = array_values($items); | |
| for ($i = count($items) - 1; $i > 0; $i--) | |
| { | |
| $j = @mt_rand(0, $i); | |
| $tmp = $items[$i]; | |
| $items[$i] = $items[$j]; | |
| $items[$j] = $tmp; | |
| } | |
| foreach($items as $k => $v) { | |
| foreach($di as $dk => $dv) { | |
| if($v == $dv) { | |
| $items[$dk] = $dv; | |
| unset($items[$k]); | |
| } | |
| } | |
| } | |
| } | |
| //Example seed: | |
| $id = 1; | |
| //Example assoc. array: | |
| $ph = [ | |
| 'one' => 'One', | |
| 'two' => 'Two', | |
| 'three' => 'Three', | |
| 'four' => 'Four', | |
| 'five' => 'Five', | |
| 'six' => 'Six' | |
| ]; | |
| fisherYatesShuffleAssoc($ph, $id); | |
| print_r($ph); | |
| /* Returns: | |
| Array | |
| ( | |
| [four] => Four | |
| [six] => Six | |
| [three] => Three | |
| [one] => One | |
| [five] => Five | |
| [two] => Two | |
| ) | |
| */ | |
| ?> |
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