php 数组

//筛选奇数
function test_odd($var)
{
    return ($var & 1);
}
$a1=array("a","b",2,3,4,43,21);
print_r(array_filter($a1,"test_odd"));

$start=time();
$a=[[‘name‘=>‘jack‘,‘age‘=>22],[‘name‘=>‘rose‘,‘age‘=>12]];
$res=array_map(function ($s){return $s[‘age‘];},$a);
print_r(time()-$start);
print_r($res);
//说明此种方式要比foreach更节约时间