Detailed explanation of the shuffle function of PHP that disrupts arrays

This article will mainly introduce the shuffle function of PHP to disrupt the array. Sharing it with everyone as a reference, I hope it will be helpful to everyone.

shuffle()

PHP shuffle() function randomly arranges the order of array cells (shuffles the array). This function assigns new keys to the elements in the array. This will delete the original keys rather than just reorder them.

Syntax:

bool shuffle (array &array)

Example 1:

<?php
$arr = range(1,8);
print_r($arr);
echo &#39;<br />&#39;;
shuffle($arr);
print_r($arr);
?>

Run this example output:

Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 [6] => 7 [7] => 8 ) 
Array ( [0] => 6 [1] => 1 [2] => 3 [3] => 2 [4] => 5 [5] => 7 [6] => 8 [7] => 4 )

It should be noted that every time the page is refreshed, the print_r($arr) result after shuffle($arr) is different. Since PHP 4.2.0, it is no longer necessary to use functions such as srand() to seed the random number generator and the system will automatically complete it.

Example 2, using associative array:

<?php
$arr = array("a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5);
shuffle($arr);
print_r($arr);
?>

Run this example output:

Array ( [0] => ; 5 [1] => 2 [2] => 1 [3] => 3 [4] => 4 )

Of course, the output result will be different every time the page is refreshed of.

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