ARRAY_MULTISORT(3)							 1							ARRAY_MULTISORT(3)

array_multisort - Sort multiple or multi-dimensional arrays

SYNOPSIS

       bool array_multisort (array  &$array1, [mixed  $array1_sort_order = SORT_ASC], [mixed  $array1_sort_flags = SORT_REGULAR], [mixed  $...])

DESCRIPTION

       array_multisort(3) can be used to sort several arrays at once, or a multi-dimensional array by one or more dimensions.

	Associative ( string) keys will be maintained, but numeric keys will be re-indexed.

PARAMETERS

	      o $array1
		- An array being sorted.

	      o $array1_sort_order
		- The order used to sort the previous array argument. Either SORT_ASC to sort ascendingly or SORT_DESC to sort descendingly.  This
		argument can be swapped with $array1_sort_flags or omitted entirely, in which case SORT_ASC is assumed.

	      o $array1_sort_flags
		- Sort options for the previous array argument:  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. It uses the locale, which can be changed  using
		       setlocale(3)

		     o SORT_NATURAL - compare items as strings using "natural ordering" like natsort(3)

		     o SORT_FLAG_CASE - can be combined (bitwise OR) with SORT_STRING or SORT_NATURAL to sort strings case-insensitively

	       This argument can be swapped with $array1_sort_order or omitted entirely, in which case SORT_REGULAR is assumed.

	      o $...
		-  More arrays, optionally followed by sort order and flags. Only elements corresponding to equivalent elements in previous arrays
		are compared. In other words, the sort is lexicographical.

RETURN VALUES

	Returns TRUE on success or FALSE on failure.

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.4.0	|						    |
       |	|						    |
       |	|  The SORT_NATURAL and SORT_FLAG_CASE	were  added |
       |	| to $array1_sort_flags as possible sort flags.     |
       |	|						    |
       | 5.3.0	|						    |
       |	|						    |
       |	|  The	   SORT_LOCALE_STRING	 was	added	 to |
       |	| $array1_sort_flags as possible sort flags.	    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES

       Example #1

	      Sorting multiple arrays

	      <?php
	      $ar1 = array(10, 100, 100, 0);
	      $ar2 = array(1, 3, 2, 4);
	      array_multisort($ar1, $ar2);

	      var_dump($ar1);
	      var_dump($ar2);
	      ?>

	       In this example, after sorting, the first array will contain 0, 10, 100, 100. The second array will contain 4, 1, 2, 3. The entries
	      in the second array corresponding to the identical entries in the first array (100 and 100) were sorted as well.

	      array(4) {
		[0]=> int(0)
		[1]=> int(10)
		[2]=> int(100)
		[3]=> int(100)
	      }
	      array(4) {
		[0]=> int(4)
		[1]=> int(1)
		[2]=> int(2)
		[3]=> int(3)
	      }

       Example #2

	      Sorting multi-dimensional array

	      <?php
	      $ar = array(
		     array("10", 11, 100, 100, "a"),
		     array(   1,  2, "2",   3,	 1)
		    );
	      array_multisort($ar[0], SORT_ASC, SORT_STRING,
			      $ar[1], SORT_NUMERIC, SORT_DESC);
	      var_dump($ar);
	      ?>

	       In  this  example,  after sorting, the first array will transform to "10", 100, 100, 11, "a" (it was sorted as strings in ascending
	      order). The second will contain 1, 3, "2", 2, 1 (sorted as numbers, in descending order).

	      array(2) {
		[0]=> array(5) {
		  [0]=> string(2) "10"
		  [1]=> int(100)
		  [2]=> int(100)
		  [3]=> int(11)
		  [4]=> string(1) "a"
		}
		[1]=> array(5) {
		  [0]=> int(1)
		  [1]=> int(3)
		  [2]=> string(1) "2"
		  [3]=> int(2)
		  [4]=> int(1)
		}
	      }

       Example #3

	      Sorting database results

	       For this example, each element in the $data array represents one row in a table. This  type  of	dataset  is  typical  of  database
	      records.

	       Example data:

	      volume | edition
	      -------+--------
		  67 |	     2
		  86 |	     1
		  85 |	     6
		  98 |	     2
		  86 |	     6
		  67 |	     7

	       The data as an array, called $data. This would usually, for example, be obtained by looping with mysql_fetch_assoc(3).

	      <?php
	      $data[] = array('volume' => 67, 'edition' => 2);
	      $data[] = array('volume' => 86, 'edition' => 1);
	      $data[] = array('volume' => 85, 'edition' => 6);
	      $data[] = array('volume' => 98, 'edition' => 2);
	      $data[] = array('volume' => 86, 'edition' => 6);
	      $data[] = array('volume' => 67, 'edition' => 7);
	      ?>

	       In this example, we will order by $volume descending, $edition ascending.

	       We have an array of rows, but array_multisort(3) requires an array of columns, so we use the below code to obtain the columns, then
	      perform the sorting.

	      <?php
	      // Obtain a list of columns
	      foreach ($data as $key => $row) {
		  $volume[$key]  = $row['volume'];
		  $edition[$key] = $row['edition'];
	      }

	      // Sort the data with volume descending, edition ascending
	      // Add $data as the last parameter, to sort by the common key
	      array_multisort($volume, SORT_DESC, $edition, SORT_ASC, $data);
	      ?>

	       The dataset is now sorted, and will look like this:

	      volume | edition
	      -------+--------
		  98 |	     2
		  86 |	     1
		  86 |	     6
		  85 |	     6
		  67 |	     2
		  67 |	     7

       Example #4

	      Case insensitive sorting

	       Both SORT_STRING and SORT_REGULAR are case sensitive, strings starting with a capital letter will come before strings starting with
	      a lowercase letter.

	       To perform a case insensitive search, force the sorting order to be determined by a lowercase copy of the original array.

	      <?php
	      $array = array('Alpha', 'atomic', 'Beta', 'bank');
	      $array_lowercase = array_map('strtolower', $array);

	      array_multisort($array_lowercase, SORT_ASC, SORT_STRING, $array);

	      print_r($array);
	      ?>

	      The above example will output:

	      Array
	      (
		  [0] => Alpha
		  [1] => atomic
		  [2] => bank
		  [3] => Beta
	      )

SEE ALSO

       usort(3), The comparison of array sorting functions.

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