(PHP 4, PHP 5, PHP 7)
usort — 使锟斤拷锟矫伙拷锟皆讹拷锟斤拷谋冉虾锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷械锟街碉拷锟斤拷锟斤拷锟斤拷锟�
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Note:
If two members compare as equal, their relative order in the sorted array is undefined.
Note: 锟剿猴拷锟斤拷为
array锟叫碉拷元锟截革拷锟斤拷锟铰的硷拷锟斤拷锟斤拷锟解将删锟斤拷原锟叫的硷拷锟斤拷锟斤拷锟斤拷锟斤拷锟角斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷
array锟斤拷锟斤拷锟斤拷锟斤拷锟�
cmp_function锟节碉拷一锟斤拷锟斤拷锟斤拷小锟节ｏ拷锟斤拷锟节伙拷锟斤拷诘诙锟斤拷锟斤拷锟斤拷锟绞憋拷锟斤拷帽冉虾锟斤拷锟斤拷锟斤拷锟斤拷锟接︼拷胤锟斤拷锟揭伙拷锟叫★拷冢锟斤拷锟斤拷诨锟斤拷锟斤拷 0 锟斤拷锟斤拷锟斤拷锟斤拷
锟缴癸拷时锟斤拷锟斤拷 TRUE锟斤拷 锟斤拷锟斤拷锟斤拷失锟斤拷时锟斤拷锟斤拷 FALSE锟斤拷
Example #1 usort() 锟斤拷锟斤拷
<?php
function cmp($a, $b)
{
if ($a == $b) {
return 0;
}
return ($a < $b) ? -1 : 1;
}
$a = array(3, 2, 5, 6, 1);
usort($a, "cmp");
foreach ($a as $key => $value) {
echo "$key: $value\n";
}
?>
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
0: 1 1: 2 2: 3 3: 5 4: 6
Note:
锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟叫★拷锟斤拷锟斤拷锟斤拷锟� sort() 锟斤拷锟斤拷锟斤拷锟斤拷锟绞★拷
Example #2 使锟矫讹拷维锟斤拷锟斤拷锟� usort() 锟斤拷锟斤拷
<?php
function cmp($a, $b)
{
return strcmp($a["fruit"], $b["fruit"]);
}
$fruits[0]["fruit"] = "lemons";
$fruits[1]["fruit"] = "apples";
$fruits[2]["fruit"] = "grapes";
usort($fruits, "cmp");
while (list($key, $value) = each($fruits)) {
echo "$fruits[$key]: " . $value["fruit"] . "\n";
}
?>
锟斤拷锟斤拷锟斤拷锟轿拷锟斤拷锟绞憋拷锟�$a 锟斤拷 $b 锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟揭伙拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷谩锟�
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
$fruits[0]: apples $fruits[1]: grapes $fruits[2]: lemons
Example #3 usort() example using a member function of an object
<?php
class TestObj {
var $name;
function TestObj($name)
{
$this->name = $name;
}
/* This is the static comparing function: */
static function cmp_obj($a, $b)
{
$al = strtolower($a->name);
$bl = strtolower($b->name);
if ($al == $bl) {
return 0;
}
return ($al > $bl) ? +1 : -1;
}
}
$a[] = new TestObj("c");
$a[] = new TestObj("b");
$a[] = new TestObj("d");
usort($a, array("TestObj", "cmp_obj"));
foreach ($a as $item) {
echo $item->name . "\n";
}
?>
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
b c d
Example #4 usort() example using a closure to sort a multi-dimensional array
<?php
$array[0] = array('key_a' => 'z', 'key_b' => 'c');
$array[1] = array('key_a' => 'x', 'key_b' => 'b');
$array[2] = array('key_a' => 'y', 'key_b' => 'a');
function build_sorter($key) {
return function ($a, $b) use ($key) {
return strnatcmp($a[$key], $b[$key]);
};
}
usort($array, build_sorter('key_b'));
foreach ($array as $item) {
echo $item['key_a'] . ', ' . $item['key_b'] . "\n";
}
?>
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
y, a x, b z, c