How to remove specified elements from an array in php

In PHP, we often need to operate on arrays. One common operation is to delete specific elements, that is, to remove certain elements from the array. This article will introduce several methods to remove specified elements from an array, hoping to help everyone better understand the operation of PHP arrays.

1. unset() function

unset() is a function used in PHP to delete variables and can also be used to delete array elements. This function can delete one or more array elements by passing it the index of the element to be deleted as a parameter. The following is an example:

$array = array("A", "B", "C", "D", "E");
unset($array[1]); //删除索引为1的元素B
print_r($array);

Output result:

Array
(
    [0] => A
    [2] => C
    [3] => D
    [4] => E
)

In the above code, we use the unset() function to delete the index 1 (that is, the second element) in the array $array ) elements, and finally use the print_r() function to view the deleted results.

2. array_splice() function

array_splice() function can delete one or more elements from an array and replace the deleted elements with another array. When using this function, you must specify the array to be modified, the starting index of the elements to be removed, the number of elements to be removed, and the new elements to be added. The following is an example:

$array = array("A", "B", "C", "D", "E");
array_splice($array, 1, 1); //删除索引为1的元素B
print_r($array);

Output result:

Array
(
    [0] => A
    [1] => C
    [2] => D
    [3] => E
)

In the above code, we use the array_splice() function to delete the index 1 (that is, the second element) in the array $array ) elements, and use the print_r() function to view the deleted results.

3. array_diff() function

array_diff() function is used to compare the difference of two or more arrays and returns a new array containing the first array Elements that exist in , but do not exist in other arrays. This means that we can delete a specified element by comparing the element to be deleted with other elements in the array and then saving the difference to a new array. The following is an example:

$array = array("A", "B", "C", "D", "E");
$remove = array("B", "D");
$result = array_diff($array, $remove); //删除元素B和D
print_r($result);

Output result:

Array
(
    [0] => A
    [2] => C
    [4] => E
)

In the above code, we store the elements "B" and "D" to be deleted in the array $remove, and use array_diff( ) function to compare the differences in the arrays $array and $remove to get a new array $result that does not contain the elements "B" and "D" to be deleted.

4. array_filter() function

array_filter() function is used to filter elements in the array that do not meet certain conditions and return a new array containing elements that meet the conditions. element. This function can accept two parameters: the array to filter and a callback function. The callback function is used to detect each element in the array and return a Boolean value indicating whether the element meets the condition. If the callback function returns true, the element in the array will be included in the new array, otherwise it will be ignored. The following is an example:

$array = array("A", "B", "C", "D", "E");
$remove = array("B", "D");
$result = array_filter($array, function($value) use ($remove) {
    return !in_array($value, $remove);
}); //删除元素B和D
print_r($result);

Output result:

Array
(
    [0] => A
    [2] => C
    [4] => E
)

In the above code, we store the elements "B" and "D" to be deleted in the array $remove, and use array_filter( ) function to filter the array $array to obtain a new array $result, which does not contain the elements "B" and "D" to be deleted.

Summary

The above are several methods for removing specified elements from an array. Each method has its applicable scenarios, advantages and disadvantages. In practical applications, the appropriate method can be selected according to the specific situation. Hope this article can be helpful to everyone.

The above is the detailed content of How to remove specified elements from an array in php. For more information, please follow other related articles on the PHP Chinese website!