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Sorting Arrays

PHP has several functions that deal with sorting arrays, and this document exists to help sort it all out.

The main differences are:

Sorting function attributes
Function name Sorts by Maintains key association Order of sort Related functions
array_multisort() value associative yes, numeric no first array or sort options array_walk()
asort() value yes low to high arsort()
arsort() value yes high to low asort()
krsort() key yes high to low ksort()
ksort() key yes low to high asort()
natcasesort() value yes natural, case insensitive natsort()
natsort() value yes natural natcasesort()
rsort() value no high to low sort()
shuffle() value no random array_rand()
sort() value no low to high rsort()
uasort() value yes user defined uksort()
uksort() key yes user defined uasort()
usort() value no user defined uasort()


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PHP手册 - N: Sorting Arrays

用户评论:

oculiz at gmail dot com (12-Mar-2011 05:57)

Another way to do a case case-insensitive sort by key would simply be:

<?php
uksort
($array, 'strcasecmp');
?>

Since strcasecmp is already predefined in php it saves you the trouble to actually write the comparison function yourself.

K.i.n.g.d.r.e.a.d (06-Apr-2010 02:29)

If you search a feature which sorts an array incasesensitive by key, try this:

<?php
function isort($a,$b) {
    return
strtolower($a)>strtolower($b);
}
uksort($array, "isort");
?>

Dirk (29-Mar-2010 09:32)

If you need to perform any of these sort functions on an array containing two or more equivalent values, you can get the equivalents to fall next to each other within the overall ordering (similar to how MySQL's ORDER BY works...) instead of breaking the sort() function, by using ksort() as a second parameter to arbitrarily distinguish any equivalent values by their unique keys:

<?php

sort
($array, ksort($array));

?>

Seems like this effect should be built in.  At least the workaround is so short...