给定这个数组:
$inventory = array(
array("type"=>"fruit", "price"=>3.50),
array("type"=>"milk", "price"=>2.90),
array("type"=>"pork", "price"=>5.43),
);
我想按价格排序$inventory的元素，以获得:
$inventory = array(
array("type"=>"pork", "price"=>5.43),
array("type"=>"fruit", "price"=>3.50),
array("type"=>"milk", "price"=>2.90),
);
我该怎么做呢?
当前回答
$inventory =
array(array("type"=>"fruit", "price"=>3.50),
array("type"=>"milk", "price"=>2.90),
array("type"=>"pork", "price"=>5.43),
);
function pricesort($a, $b) {
$a = $a['price'];
$b = $b['price'];
if ($a == $b)
return 0;
return ($a > $b) ? -1 : 1;
}
usort($inventory, "pricesort");
// uksort($inventory, "pricesort");
print("first: ".$inventory[0]['type']."\n\n");
// for usort(): prints milk (item with lowest price)
// for uksort(): prints fruit (item with key 0 in the original $inventory)
// foreach prints the same for usort and uksort.
foreach($inventory as $i){
print($i['type'].": ".$i['price']."\n");
}
输出:
first: pork
pork: 5.43
fruit: 3.5
milk: 2.9
其他回答
如果需要对不同大小写的字符串数组进行排序，这将把排序数组的值更改为小写。
$data = [
[
'name' => 'jack',
'eyeColor' => 'green'
],
[
'name' => 'Amy',
'eyeColor' => 'brown'
],
[
'name' => 'Cody',
'eyeColor' => 'blue'
]
];
function toLowerCase($a) { return strtolower($a); }
$sortArray = array_map("toLowerCase",array_column($data, 'name'));
array_multisort($sortArray, SORT_ASC, $data);
您可以尝试定义自己的比较函数，然后使用usort。
试试这个:
asort($array_to_sort, SORT_NUMERIC);
参考如下: http://php.net/manual/en/function.asort.php
在这里查看各种排序标志: http://www.php.net/manual/en/function.sort.php
$inventory =
array(array("type"=>"fruit", "price"=>3.50),
array("type"=>"milk", "price"=>2.90),
array("type"=>"pork", "price"=>5.43),
);
function pricesort($a, $b) {
$a = $a['price'];
$b = $b['price'];
if ($a == $b)
return 0;
return ($a > $b) ? -1 : 1;
}
usort($inventory, "pricesort");
// uksort($inventory, "pricesort");
print("first: ".$inventory[0]['type']."\n\n");
// for usort(): prints milk (item with lowest price)
// for uksort(): prints fruit (item with key 0 in the original $inventory)
// foreach prints the same for usort and uksort.
foreach($inventory as $i){
print($i['type'].": ".$i['price']."\n");
}
输出:
first: pork
pork: 5.43
fruit: 3.5
milk: 2.9
因为数组元素本身就是带有字符串键的数组，所以最好定义一个自定义比较函数。做起来又快又简单。试试这个:
function invenDescSort($item1,$item2)
{
if ($item1['price'] == $item2['price']) return 0;
return ($item1['price'] < $item2['price']) ? 1 : -1;
}
usort($inventory,'invenDescSort');
print_r($inventory);
产生以下结果:
Array
(
[0] => Array
(
[type] => pork
[price] => 5.43
)
[1] => Array
(
[type] => fruit
[price] => 3.5
)
[2] => Array
(
[type] => milk
[price] => 2.9
)
)
