无论如何要计算一个数组在Php中有多少键？

Question

Array
    (
        [0] => 'hello'
        [1] => 'there'
        [2] => 
        [3] => 
        [4] => 3
    )

// how to  get the number 5?

Answer 1

计数

$arr = Array
    (
        0 => 'hello',
        1 => 'there',
        2 => null,
        3 => null,
        4 => 3,
    );
var_dump(count($arr));

输出:

INT(5)