How to delete array elements if php doesn't know the key value

Delete method: 1. Use the "unset(array[key name])" statement to delete; 2. Use the "array_splice(array, element position, 1)" statement to delete; 3. Use "array_diff_key(array, [ "Key name" => ""])" statement is deleted.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

1. Use the unset() function Delete elements according to the key name of the array element

<?php
$array = array(0 => "a", 1 => "b", 2 => "c");
unset($array[1]);
           //↑ 你要删除的数组元素值的键名
print_r($array);
?>

Output result:

Array (
    [0] => a
    [2] => c
)

2. Use the array_splice() function to delete elements according to the position of the array element

If you use the array_splice() function, the keys of the array will be automatically re-indexed, but it will not work for associative arrays. You need to use array_values() to convert the keys to numeric keys.

<?php
$array = array(0 => "a", 1 => "b", 2 => "c");
array_splice($array, 1, 1);
                   //↑ 要删除元素的开始位置（0 = 第一个元素，1 = 第二个元素）
print_r($array);
?>

Output result:

Array
(
    [0] => a
    [1] => c
)

3. Use the array_diff_key() function

If you know the key of the array element to be deleted, You can use array_diff_key(). You need to enter the key to be deleted in the key value position of the second parameter of the function. The value is not required and can be optional.

<?php
$array = array(0 => "a", 1 => "b", 2 => "c");
$array = array_diff_key($array, [0 => "", "2" => ""]);
                               //↑           ↑ 你要删除的数组键名
print_r($array);
?>

The output result is:

Array (
    [1] => b
)

Recommended learning: "PHP Video Tutorial"

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