Description
bool
array_multisort ( array ar1 [, mixed arg [, mixed ... [, array ...]]])
array_multisort() can be used to sort several
arrays at once or a multi-dimensional array according by one of
more dimensions. Associative (string) keys are maintained while
numerical keys are re-indexed.
The input arrays are treated as columns of a table to be sorted
by rows - this resembles the functionality of SQL ORDER BY
clause. The first array is the primary one to sort by. The rows
(values) in that array that compare the same are sorted by the
next input array, and so on.
The argument structure of this function is a bit unusual, but
flexible. The very first argument has to be an
array. Subsequently, each argument can be either an array or a
sorting flag from the following lists.
Sorting order flags:
Sorting type flags:
SORT_REGULAR - compare items normally
SORT_NUMERIC - compare items numerically
SORT_STRING - compare items as strings
No two sorting flags of the same type can be specified after each
array. The sorting flags specified after an array argument apply
only to that array - they are reset to default SORT_ASC and
SORT_REGULAR before each new array argument.
Returns TRUE on success or FALSE on failure.
Example 1. Sorting multiple arrays |
<?php
$ar1 = array("10", 100, 100, "a");
$ar2 = array(1, 3, "2", 1);
array_multisort($ar1, $ar2);
?>
|
|
In this example, after sorting, the first array will contain 10,
"a", 100, 100. The second array will contain 1, 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.
Example 2. Sorting multi-dimensional array |
<?php
$ar = array(array("10", 100, 100, "a"), array(1, 3, "2", 1));
array_multisort($ar[0], SORT_ASC, SORT_STRING,
$ar[1], SORT_NUMERIC, SORT_DESC);
?>
|
|
In this example, after sorting, the first array will contain 10,
100, 100, "a" (it was sorted as strings in ascending order), and
the second one will contain 1, 3, "2", 1 (sorted as numbers, in
descending order).
