array_splice()用于关联数组

$array = array("a", "b", "c", "d", "e");
$insert_array = array("x", "y", "z");

// 在索引 2 处插入 $insert_array
array_splice($array, 2, 0, $insert_array);

print_r($array);

Array
(
    [0] => a
    [1] => b
    [2] => x
    [3] => y
    [4] => z
    [5] => c
    [6] => d
    [7] => e
)

// 删除索引 2 处的元素
array_splice($array, 2, 1);

// 替换索引 2 处的元素
$replace_array = array("m", "n");
array_splice($array, 2, 1, $replace_array);

$assoc_array = array(
    "a" => "apple",
    "b" => "banana",
    "c" => "cherry",
    "d" => "date",
    "e" => "elderberry"
);

// 在关联数组中插入元素
$insert_assoc_array = array(
    "x" => "xenon",
    "y" => "yttrium",
    "z" => "zirconium"
);

array_splice($assoc_array, 2, 0, $insert_assoc_array);

print_r($assoc_array);

Array
(
    [a] => apple
    [b] => banana
    [x] => xenon
    [y] => yttrium
    [z] => zirconium
    [c] => cherry
    [d] => date
    [e] => elderberry
)