note 82579 deleted from function.mt-rand by cmb
| From: | cmb@php.net | Date: | Sun, 19 Jan 2020 08:39:34 +0000 |
| Subject: | note 82579 deleted from function.mt-rand by cmb | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-213917@lists.php.net to get a copy of this message | ||
Note Submitter: Jonathon
----
Below, andrei suggested a function for generating a list of unique integers, randomly arranged. In
response to a note below that his solution is inefficient, I'm providing an O(N) solution which
should be much more efficient, yet still yield a good guarantee of producing randomly ordered
integers.
<?php
function SwapShuffle($min, $max) {
$last = $max - $min;
for ($i=0; $i<=$last; $i++) {
$arr[$i] = $min + $i;
}
for ($run=0; $run<7; $run++) {
for ($i=0; $i<=$last; $i++) {
$target = mt_rand(0, $last);
$swap = $arr[$target];
$arr[$target] = $arr[$i];
$arr[$i] = $swap;
}
}
return $arr;
}
// Call as:
$result = SwapShuffle(10, 30);
foreach ($result as $num) {
echo "$num\n";
}
?>