(PHP 4 >= 4.0.0)
array_multisort -- Sort multiple or multi-dimensional arrays
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. It maintains key association when sorting.
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 after before each new array argument.
Returns TRUE on success, FALSE on failure.
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Example 1. Sorting multiple arrays
$ar1 = array ("10", 100, 100, "a");
$ar2 = array (1, 3, "2", 1);
array_multisort ($ar1, $ar2);
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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.
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Example 2. Sorting multi-dimensional array
$ar = array (array ("10", 100, 100, "a"), array (1, 3, "2", 1));
array_multisort ($ar[0], SORT_ASC, SORT_STRING,
$ar[1], SORT_NUMERIC, SORT_DESC);
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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).
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