Question

关php二维数组中按某个元素的值排序

array([0] => array(
['id'] => 1['type'] => '普通发票'['weight'] => 1['is_start'] => 1)
[1] => array(
['id'] => 2['type'] => '增值税专用发票'['weight'] => 2['is_start'] => 1)
[2] => array(
['id'] => 3['type'] => '收据'['weight'] => 0['is_start'] => 1)
[3] => array(
['id'] => 4['type'] => '测试'['weight'] => 4['is_start'] => 0)
)

我想重新排序数组，用weight的值来排序第一层
得到的结果的应该是如下这样：

array(
[0] => array(
['id'] => 3['type'] => '收据'['weight'] => 0['is_start'] => 1)
[1] => array(
['id'] => 1['type'] => '普通发票'['weight'] => 1['is_start'] => 1)
[2] => array(
['id'] => 2['type'] => '增值税专用发票'['weight'] => 2['is_start'] => 1)
[3] => array(
['id'] => 4['type'] => '测试'['weight'] => 4['is_start'] => 0)
)

假定这个数组的为$invoice，要如何去操作它？
PHP有很多数组函数可以利用，但是不知道哪个才是。

Answer 1

$fruits =array(
0 => array( 'id' => 1, 'type' => '普通发票', 'weight' => 1, 'is_start' => 1),
1 => array( 'id' => 2, 'type' => '增值税专用发票', 'weight' => 2, 'is_start' => 1),
2 => array( 'id' => 3, 'type' => '收据', 'weight' => 0, 'is_start' => 1),
3 => array( 'id' => 4, 'type' => '测试', 'weight' => 4, 'is_start' => 0)
);

var_dump($fruits);

function compare($x,$y)
{
if($x['weight'] == $y['weight'])
return 0;
elseif($x['weight'] < $y['weight'])
return -1;
else
return 1;
}
usort($fruits,"compare");
echo $fruits[0]['id']."<br />";
echo $fruits[1]['id']."<br />";
echo $fruits[2]['id']."<br />";
echo $fruits[3]['id']."<br />";

Answer 2

参考手册的array_multisort()