This article demonstrates a PHP function which can be used for swapping of keys with values in an array. array_flip() is the function which accepts an array as parameter and exchange the keys with their associated values in an array. This function returns an array with flipped values.

Note :

• If any value has multiple occurrences, the last key will be used as value other keys will be lost.
• Warning will be generated, if the values of an array are not valid keys i.e. integer or string values.

Syntax : array_flip(array)

array : Specifies an array, whose key/value pairs have to be flipped.

Example :

<?php
   $arr = array(1 => "a", 2 => "b", 3 => "c", 4 => "d", 5 => "e");
   print_r($arr);
   echo "<br>";
   echo "After Flip : ";
   print_r(array_flip($arr));
?>

Output :
Array ( [1] => a [2] => b [3] => c [4] => d [5] => e )
After Flip : Array ( [a] => 1 [b] => 2 [c] => 3 [d] => 4 [e] => 5 )