PHP array_multisort() Function: Sorting Multiple Arrays or Multidimensional Arrays

array_multisort() can be used to sort multiple arrays at once, or to sort a multidimensional array based on one or more dimensions.

String keys remain unchanged, while numeric keys are re‑indexed.

Sorting order flags:

SORT_ASC – ascending order

SORT_DESC – descending order

Sorting type flags:

SORT_REGULAR – standard comparison

SORT_NUMERIC – numeric comparison

SORT_STRING – string comparison

Each array can have only one sorting flag; default flags are SORT_ASC and SORT_REGULAR.

The input arrays are treated as columns of a table and sorted by rows, similar to SQL’s ORDER BY clause. The first array is the primary sort key; if values are equal, subsequent arrays are used.

Function signature:

bool array_multisort(array &$arr, mixed $arg = SORT_ASC, ...)

Parameters:

arr : The array to be sorted.

arg : Additional arrays or sorting flag constants (SORT_ASC, SORT_DESC, SORT_REGULAR, SORT_NUMERIC, SORT_STRING).

... : Additional array variables for recursive merging.

Return value: TRUE on success, FALSE on failure.

Example:

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

Output:

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