在PHP中对关联数组进行排序[重复]
问题描述:
This question already has an answer here:
- How can I sort arrays and data in PHP? 10 answers
I have an array in this format:
Array
(
[0] => Array
(
[text] => tests
[language] =>
[advertiserCompetitionScale] => 5
[avgSearchVolume] => 7480000
[lastMonthSearchVolume] => 9140000
)
[1] => Array
(
[text] => personality tests
[language] =>
[advertiserCompetitionScale] => 5
[avgSearchVolume] => 165000
[lastMonthSearchVolume] => 201000
)
[2] => Array
(
[text] => online tests
[language] =>
[advertiserCompetitionScale] => 5
[avgSearchVolume] => 246000
[lastMonthSearchVolume] => 301000
)
)
How can I sort an array in that format, in the descending order of the avgSearchVolume
field? Is there a built in function for this?
</div>
答
Use usort
and supply your own function to do the ordering, e.g.
function cmp($a, $b)
{
return $b['avgSearchVolume'] - $a['avgSearchVolume'];
}
usort($array, "cmp");
答
You'll have to use a custom callback function together with usort()
.
function cmp($a, $b)
{
if ($a['avgSearchVolume'] == $b['avgSearchVolume']) {
return 0;
}
return ($a['avgSearchVolume'] > $b['avgSearchVolume']) ? -1 : 1;
}
usort($array, 'cmp');
答
Until PHP 5.3 this is the best function for sorting based on subkeys without making a new function for each key.
function sortBySubkey(&$array, $subkey, $sortType = SORT_ASC) {
foreach ($array as $subarray) {
$keys[] = $subarray[$subkey];
}
array_multisort($keys, $sortType, $array);
}
sortBySubkey($arr, 'avgSearchVolume');
With PHP 5.3 you can make something like this, same function call as now.
function getSortVariable($sortType = SORT_ASC) {
switch($sortType) {
case SORT_ASC:
return function ($a, $b) use ($subkey) { return strcmp($a[$subkey], $b[$subkey]); };
}
}
function sortBySubkey(&$array, $subkey, $sortType = SORT_ASC) {
$sortFunction = getSortVariable($sortType);
usort($array, $sortFunction($subkey));
}
答
Here is another solution, You can add multiple options for sorting(See the commented section of the code)
<?php
$arr=Array(
Array("text" => "tests","language" =>"","advertiserCompetitionScale" => 5,"avgSearchVolume" => 7480000,"lastMonthSearchVolume" => 9140000),
Array("text" => "personality tests","language" =>"","advertiserCompetitionScale" => 5,"avgSearchVolume" => 165000,"lastMonthSearchVolume"=>201000),
Array("text" => "online tests","language" =>"","advertiserCompetitionScale" => 5,"avgSearchVolume" => 246000,"lastMonthSearchVolume" =>301000)
);
$sort = array();
foreach($arr as $k=>$v) {
$sort['avgSearchVolume'][$k] = $v['avgSearchVolume'];
//$sort['text'][$k] = $v['text'];
}
array_multisort($sort['avgSearchVolume'], SORT_DESC, $arr);
//array_multisort($sort['avgSearchVolume'], SORT_DESC, $sort['text'], SORT_ASC,$arr);
echo "<pre>";
print_r($arr);
?>
答
function querySort ($first_Array,$second_Array) {
return strcasecmp($first_Array['name'],$second_Array['name']);
}
echo '<pre>';
usort($main, 'querySort');
print_r($main);
die;