php man page for array_search

ARRAY_SEARCH(3) 							 1							   ARRAY_SEARCH(3)

array_search - Searches the array for a given value and returns the corresponding key if successful

SYNOPSIS
       mixed array_search (mixed  $needle, array  $haystack, [bool  $strict = false])

DESCRIPTION
	Searches $haystack for $needle.

PARAMETERS
	      o $needle
		- The searched value.

	      Note

		      If $needle is a string, the comparison is done in a case-sensitive manner.

	      o $haystack
		- The array.

	      o $strict
		-  If  the  third  parameter  $strict  is  set to TRUE then the array_search(3) function will search for identical elements in the
		$haystack. This means it will also check the types of the $needle in the $haystack, and objects must be the same instance.

RETURN VALUES
	Returns the key for $needle if it is found in the array, FALSE otherwise.

	If $needle is found in $haystack more than once, the first matching key is returned. To return the  keys  for  all  matching  values,  use
       array_keys(3) with the optional $search_value parameter instead.

       Warning

	      This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. Please read the section on
	      Booleans for more information. Use the === operator for testing the return value of this function.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.3.0	|						    |
       |	|						    |
       |	|  As with all internal PHP functions as of  5.3.0, |
       |	| array_search(3)  returns  NULL if invalid parame- |
       |	| ters are passed to it.			    |
       |	|						    |
       | 4.2.0	|						    |
       |	|						    |
       |	|  Prior to PHP 4.2.0, array_search(3) returns NULL |
       |	| on failure instead of FALSE.			    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      array_search(3) example

	      <?php
	      $array = array(0 => 'blue', 1 => 'red', 2 => 'green', 3 => 'red');

	      $key = array_search('green', $array); // $key = 2;
	      $key = array_search('red', $array);   // $key = 1;
	      ?>

SEE ALSO
       array_keys(3), array_values(3), array_key_exists(3), in_array(3).

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