如何使用选定的键值对PHP多维关联数组进行排序

Question

How to sort following php array with its 'zindex' key value

$array = array('the-1'=> array('name'=>'lorem','pos'=>array('top'=>'90','left'=>'80'),'zindex'=>2),
        'the-2'=> array('name'=>'ipsum','pos'=>array('top'=>'190','left'=>'180'),'zindex'=>1),
        'the-3'=> array('name'=>'lorem ipsum','pos'=>array('top'=>'20','left'=>'30'),'zindex'=>3)
        )

Is there any php function for getting the output as follows,

$array = array(
        'the-2'=> array('name'=>'ipsum','pos'=>array('top'=>'190','left'=>'180'),'zindex'=>1),
        'the-1'=> array('name'=>'lorem','pos'=>array('top'=>'90','left'=>'80'),'zindex'=>2),
        'the-3'=> array('name'=>'lorem ipsum','pos'=>array('top'=>'20','left'=>'30'),'zindex'=>3)
        )

Answer 1

usort($array,function($el1,$el2){
    return $el1-$el2;
});

Requires PHP5.3

if you need older versions' support replace anonymous function by usual one