note 102761 added to function.shuffle
| From: | oleh dot naumko at yaN05PAMhoo dot co dot uk | Date: | Fri, 04 Mar 2011 10:50:37 +0000 |
| Subject: | note 102761 added to function.shuffle | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-177553@lists.php.net to get a copy of this message | ||
The function array_2D_permute published earlier is useful but buggy: when called more than once
within the same script, it keeps all previous values in static $permuted_array, thus creating
duplicates. The corrected version of the function makes use of the additional flag to differentiate
between 1st(external) call of array_2D_permute and all subsequent(recursive, internal) calls.
<?php
# originally published http://uk.php.net/manual/en/function.shuffle.php#62840
# Takes a non-associative 1D (vector) array of items
# and returns an array of arrays with each possible permutation
function array_2D_permute($items, $perms = array(), $isCalledRecursively = false) {
static $permuted_array;
if(!$isCalledRecursively) $permuted_array = array();
if (empty($items)) {
$permuted_array[]=$perms;
} else {
for ($i = count($items) - 1; $i >= 0; --$i) {
$newitems = $items;
$newperms = $perms;
list($foo) = array_splice($newitems, $i, 1);
array_unshift($newperms, $foo);
array_2D_permute($newitems, $newperms, true);
}
return $permuted_array;
}
}
// NB now that this bug has been corrected, both produced results will be identical
$arr=array("Architecture","Mexico");
$result1=array_2D_permute($arr);
print_r($result1);
$result2=array_2D_permute($arr);
print_r($result2);
?>
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Server IP: 92.48.74.199
Probable Submitter: 195.33.27.190
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Manual Page -- http://www.php.net/manual/en/function.shuffle.php
Edit -- https://master.php.net/note/edit/102761
Del: integrated -- https://master.php.net/note/delete/102761/integrated
Del: useless -- https://master.php.net/note/delete/102761/useless
Del: bad code -- https://master.php.net/note/delete/102761/bad+code
Del: spam -- https://master.php.net/note/delete/102761/spam
Del: non-english -- https://master.php.net/note/delete/102761/non-english
Del: in docs -- https://master.php.net/note/delete/102761/in+docs
Del: other reasons-- https://master.php.net/note/delete/102761
Reject -- https://master.php.net/note/reject/102761
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