php PHP按项目数对多维数组进行排序
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PHP Sort a multidimensional array by number of items
提问by Aviram
I have an array such as:
我有一个数组，例如：
Array
(
[DEF] => Array
(
[0] => Array
(
[type] => 1
[id] => 1212
[name] => Jane Doe
[current] => 1
)
[1] => Array
(
[type] => 1
[id] => 3123121
[name] => Door
[current] =>
)
)
[ABC] => Array
(
[0] => Array
(
[type] => 1
[id] => 1234
[name] => John Doe
[current] =>
)
)
[WW] => Array
(
[0] => Array
(
[type] => 1
[id] => 1212
[name] => Jane Doe
[current] => 1
)
[1] => Array
(
[type] => 1
[id] => 3123121
[name] => Door
[current] =>
)
[2] => Array
(
[type] => 1
[id] => 64646
[name] => Floor
[current] =>
)
)
)
And I want to sort this array by number ( count() ) of inner-array items descending (i.e. most items first), so I will have this array:
我想按数组内部项目的数量（ count() ）降序（即大多数项目在前）对这个数组进行排序，所以我将拥有这个数组：
Array
(
[WW] => Array
(
[0] => Array
(
[type] => 1
[id] => 1212
[name] => Jane Doe
[current] => 1
)
[1] => Array
(
[type] => 1
[id] => 3123121
[name] => Door
[current] =>
)
[2] => Array
(
[type] => 1
[id] => 64646
[name] => Floor
[current] =>
)
)
[DEF] => Array
(
[0] => Array
(
[type] => 1
[id] => 1212
[name] => Jane Doe
[current] => 1
)
[1] => Array
(
[type] => 1
[id] => 3123121
[name] => Door
[current] =>
)
)
[ABC] => Array
(
[0] => Array
(
[type] => 1
[id] => 1234
[name] => John Doe
[current] =>
)
)
)
Can anyone suggest an efficient way to do so? Thanks.
任何人都可以提出一种有效的方法吗？谢谢。
回答by Arnaud Le Blanc
Using uksort:
使用uksort：
uksort($array, function($a, $b) { return count($b) - count($a); });
Using array_multisort:
使用array_multisort：
array_multisort(array_map('count', $array), SORT_DESC, $array);
With PHP < 5.3:
使用 PHP < 5.3：
function sort_cb($a, $b) {
return count($b) - count($a);
}
uksort($array, 'sort_cb');
回答by Dan Bizdadea
<?php
function cmp($a, $b)
{
if ($a == $b) {
return 0;
}
return (count($a) > count($b)) ? -1 : 1;
}
$a = array(
"AA" => array(
array('type'=>'1', 'id'=>'2'),
array('type'=>'2', 'id'=>'2')),
'BB' => array(
array('type'=>'1', 'id'=>'2'),
array('type'=>'2', 'id'=>'2'),
array('type'=>'5', 'id'=>'2')),
'CC' => array(
array('type'=>'1', 'id'=>'2'))
);
usort($a, "cmp");
print_r($a);
?>
回答by DaveRandom
$tempArr = $sortedArr = array();
foreach ($myArr as $k => $v) $tempArr[$k] = count($v);
asort($tempArr);
foreach ($tempArr as $k => $v) $sortedArr = $myArr[$k];
Note that this will break if any of the array values are not themselves arrays, you may want to add an is_array()check somewhere...
请注意，如果任何数组值本身不是数组，这将中断，您可能需要在is_array()某处添加检查...
