PHP array_search() Function

Search an array for the value "red" and return its key:

<?php
$a=array("a"=>"red","b"=>"green","c"=>"blue");
echo array_search("red",$a);
?>

Definition and Usage

The array_search() function search an array for a value and returns the key.

array_search(value, array, strict)

Parameter	Description
value	Required. Specifies the value to search for
array	Required. Specifies the array to search in
strict	Optional. If this parameter is set to TRUE, then this function will search for identical elements in the array. Possible values: true false - Default When set to true, the number 5 is not the same as the string 5 (See example 2)

Return Value:	Returns the key of a value if it is found in the array, and FALSE otherwise. If the value is found in the array more than once, the first matching key is returned.
PHP Version:	4.0.5+
PHP Changelog:	This function returns NULL if invalid parameters are passed to it (this applies to all PHP functions as of 5.3.0). As of PHP 4.2.0, this function returns FALSE on failure instead of NULL.

Search an array for the value 5 and return its key (notice the ""):

<?php
$a=array("a"=>"5","b"=>5,"c"=>"5");
echo array_search(5,$a,true);
?>