php man page for array_unique

ARRAY_UNIQUE(3) 							 1							   ARRAY_UNIQUE(3)

array_unique - Removes duplicate values from an array

SYNOPSIS
       array array_unique (array  $array, [int	$sort_flags = SORT_STRING])

DESCRIPTION
	Takes an input $array and returns a new array without duplicate values.

	Note  that  keys  are preserved. array_unique(3) sorts the values treated as string at first, then will keep the first key encountered for
       every value, and ignore all following keys. It does not mean that the key of the first related value from the unsorted $array will be kept.

       Note

	       Two elements are considered equal if and only if (string) $elem1 === (string) $elem2 i.e. when the  string  representation  is  the
	      same, the first element will be used.

PARAMETERS
	      o $array
		- The input array.

	      o $sort_flags
		- The optional second parameter $sort_flags may be used to modify the sorting behavior using these values:  Sorting type flags:

		     o SORT_REGULAR - compare items normally (don't change types)

		     o SORT_NUMERIC - compare items numerically

		     o SORT_STRING - compare items as strings

		     o SORT_LOCALE_STRING - compare items as strings, based on the current locale.

RETURN VALUES
	Returns the filtered array.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       |5.2.10	|						    |
       |	|						    |
       |	|  Changed the default value of $sort_flags back to |
       |	| SORT_STRING.					    |
       |	|						    |
       | 5.2.9	|						    |
       |	|						    |
       |	|  Added the  optional	$sort_flags  defaulting  to |
       |	| SORT_REGULAR.  Prior to 5.2.9, this function used |
       |	| to sort the array with SORT_STRING internally.    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      array_unique(3) example

	      <?php
	      $input = array("a" => "green", "red", "b" => "green", "blue", "red");
	      $result = array_unique($input);
	      print_r($result);
	      ?>

	      The above example will output:

	      Array
	      (
		  [a] => green
		  [0] => red
		  [1] => blue
	      )

       Example #2

	      array_unique(3) and types

	      <?php
	      $input = array(4, "4", "3", 4, 3, "3");
	      $result = array_unique($input);
	      var_dump($result);
	      ?>

	      The above example will output:

	      array(2) {
		[0] => int(4)
		[2] => string(1) "3"
	      }

SEE ALSO
       array_count_values(3).

NOTES
       Note

	       Note that array_unique(3) is not intended to work on multi dimensional arrays.

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