php man page for array_flip

ARRAY_FLIP(3)								 1							     ARRAY_FLIP(3)

array_flip - Exchanges all keys with their associated values in an array

SYNOPSIS
       array array_flip (array	$array)

DESCRIPTION
       array_flip(3) returns an array in flip order, i.e. keys from $array become values and values from $array become keys.

	Note  that the values of $array need to be valid keys, i.e. they need to be either integer or string. A warning will be emitted if a value
       has the wrong type, and the key/value pair in question will not be included in the result.

	If a value has several occurrences, the latest key will be used as its value, and all others will be lost.

PARAMETERS
	      o $array
		- An array of key/value pairs to be flipped.

RETURN VALUES
	Returns the flipped array on success and NULL on failure.

EXAMPLES
       Example #1

	      array_flip(3) example

	      <?php
	      $input = array("oranges", "apples", "pears");
	      $flipped = array_flip($input);

	      print_r($flipped);
	      ?>

	      The above example will output:

	      Array
	      (
		  [oranges] => 0
		  [apples] => 1
		  [pears] => 2
	      )

       Example #2

	      array_flip(3) example : collision

	      <?php
	      $input = array("a" => 1, "b" => 1, "c" => 2);
	      $flipped = array_flip($input);

	      print_r($flipped);
	      ?>

	      The above example will output:

	      Array
	      (
		  [1] => b
		  [2] => c
	      )

SEE ALSO
       array_values(3), array_keys(3), array_reverse(3).

PHP Documentation Group 													     ARRAY_FLIP(3)