array_key_first
(PHP 7 >= 7.3.0)
array_key_first — Gets the first key of an array
说明
Get the first key of the given array
without affecting the internal array pointer.
参数
-
array
-
An array.
返回值
Returns the first key of array
if the array is not empty; NULL
otherwise.
范例
Example #1 Basic array_key_first() Usage
<?php
$array = ['a' => 1, 'b' => 2, 'c' => 3];
$firstKey = array_key_first($array);
var_dump($firstKey);
?>
以上例程会输出:
string(1) "a"
参见
- array_key_last() - Gets the last key of an array
- reset() - 将数组的内部指针指向第一个单元