How to remove redundant elements from php array?

How to remove redundant elements from PHP arrays: 1. To delete an element in the data, you can use the [unset()] method and the [array_splice()] method; 2. To delete multiple elements in the array, you can Use the [array_diff()] method and the [array_diff_key()] method.

How to remove redundant elements from a php array:

1. Delete an element in the data

If you want to delete an element in the array, you can use the unset() or array_splice() method.

If you know the value of an array element but not the key, you can use array_search() to get the key.

1. Unset() method

Note that if you use the unset() method, it will not change other keys. If you want to change other keys, To re-sort the keys, you can use array_values().

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

Output result:

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

2. array_splice() method

If you use the array_splice() method, the keys of the array will be automatically re-established Indexing, but does not work for associative arrays, requires array_values() to convert the keys to numeric keys.

<?php
$array = array(0 => "a", 1 => "b", 2 => "c");
array_splice($array, 1, 1);
                   //↑ Offset which you want to delete
print_r($array);
?>

Output result:

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

array_splice() has the same effect as the unset() function in releasing the specified elements of the array.

2. Delete multiple elements in the array

If you want to delete multiple elements in the array, can’t you use the unset() or array_splice() function? , you need to use the array_diff() or array_diff_key() method, which requires knowing the key or value to be deleted.

1. array_diff() method

If you know the array elements you want to delete, you can use array_diff().

<?php
$array = array(0 => "a", 1 => "b", 2 => "c");
$array = array_diff($array, ["a", "c"]);
                          //└────────┘→你要删除的元素
print_r($array );
?>

The output result is:

Array
(
    [1] => b
)

2. array_diff_key() method

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 => "xy", "2" => "xy"]);
                               //↑           ↑ 你要删除的数组键
print_r($array);
?>

The output result is:

Array (
    [1] => b
)

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