array_multisort() can be used to sort several
arrays at once, or a multi-dimensional array by one or more
Associative (string) keys will be maintained, but numeric
keys will be 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 first argument has to be an array. Subsequently,
each argument can be either an array or a sorting flag from the
Sorting order flags:
SORT_ASC - Sort in ascending order
SORT_DESC - Sort in descending order
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.
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.
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).