PHP获取数组中某元素的位置及array_keys函数应用

<?php
print_r(get_defined_functions());
?>

array_keys(array,value,[strict])

<?php
$test=array(10,20,30,"10","20","30");
print_r(array_keys($test,"10",true));//严格匹配模式
//输出：
//Array ( [0] => 3)
?>