array_key_first

(PHP 7 >= 7.3.0)

array_key_first — Gets the first key of an array

说明

array_key_first ( array $array ) : mixed

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

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