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Sort an array by keys using a user-defined comparison function


uksort

(PHP 4, PHP 5)

uksortSort an array by keys using a user-defined comparison function

Description

bool uksort ( array &$array , callback $cmp_function )

uksort() will sort the keys of an array using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function.

Parameters

array

The input array.

cmp_function

The callback comparison function.

Function cmp_function should accept two parameters which will be filled by pairs of array keys. The comparison function must return an integer less than, equal to, or greater than zero if the first argument is considered to be respectively less than, equal to, or greater than the second.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 uksort() example

<?php
function cmp($a$b)
{
    
$a preg_replace('@^(a|an|the) @'''$a);
    
$b preg_replace('@^(a|an|the) @'''$b);
    return 
strcasecmp($a$b);
}

$a = array("John" => 1"the Earth" => 2"an apple" => 3"a banana" => 4);

uksort($a"cmp");

foreach (
$a as $key => $value) {
    echo 
"$key$value\n";
}
?>

The above example will output:

an apple: 3
a banana: 4
the Earth: 2
John: 1

See Also


Home>Manual>Sort an array by keys using a user-defined comparison function