How to remove an element from an array in php

PHP is a popular server-side programming language, its main features are easy to learn, easy to use and powerful functions. In PHP, array is a very common and important data type. It can be used to store a set of related data and provides many convenient operation methods, such as adding, deleting and modifying elements.

When dealing with arrays, we sometimes need to delete one or more elements from the array, which can be achieved through some of PHP's built-in functions. This article will introduce how to use PHP to remove an element from an array.

1. Use the unset function

unset is a built-in function of PHP, which can be used to delete variables, an element in an array, and the properties of an object. For arrays, we can use the unset function to delete specified elements. Its syntax is as follows:

unset($array[index]);

where $array means to delete the element The array, index represents the index value of the element to be deleted. It should be noted that after using the unset function, the index value of the deleted element will change. For example, after the original second element in the array is deleted, the original third element will become the new second element.

The following is a simple example that demonstrates how to use the unset function to delete specified elements from an array:

<?php
    $arr = array("apple", "banana", "orange", "watermelon"); //原始数组
    unset($arr[1]); //删除索引为1的元素（即“banana”）
    print_r($arr); //输出结果：Array ( [0] => apple [2] => orange [3] => watermelon )
?>

From the above example we can see that after using the unset function, " banana" element is removed from the array, and the index values ​​of other elements in the array are also changed accordingly.

2. Use the array_splice function

array_splice is another built-in function of PHP. It can be used to delete or replace elements in an array and return the deleted or replaced elements. For deleting array elements, we can use the array_splice function to pass the position and number of elements to be deleted to the function.

The syntax of the array_splice function is as follows:

array_splice($array, $start, $length);

Among them, $array represents the array from which elements are to be deleted, and $start represents The starting position of the element to be deleted, $length represents the number of elements to be deleted. It should be noted that after using the array_splice function, the index value of the deleted element will also change.

The following is an example of using the array_splice function to delete specified elements from an array:

<?php
    $arr = array("apple", "banana", "orange", "watermelon"); //原始数组
    array_splice($arr, 1, 1); //从位置1开始删除一个元素（即“banana”）
    print_r($arr); //输出结果：Array ( [0] => apple [1] => orange [2] => watermelon )
?>

From the above example we can see that after using the array_splice function, the "banana" element is removed from the array is deleted, and the index values ​​of other elements in the array also change accordingly.

3. Use the array_diff function

array_diff is another built-in function of PHP. It can be used to compare the differences between two or more arrays and return all the differences in the first array but Elements that do not appear in other arrays. For deleting one or more elements, we can use the array_diff function to move the elements to be deleted to another array and return the result after removing the target element.

The syntax of the array_diff function is as follows:

array_diff($array, $remove);

Among them, $array represents the array of elements to be deleted, and $remove represents the array to be removed. an array of elements. It should be noted that after using the array_diff function, the index value of the deleted element will not change.

The following is an example of using the array_diff function to delete specified elements from an array:

<?php
    $arr = array("apple", "banana", "orange", "watermelon"); //原始数组
    $remove = array("banana"); //需要移除的元素
    $result = array_diff($arr, $remove); //从数组中移除元素“banana”
    print_r($result); //输出结果：Array ( [0] => apple [2] => orange [3] => watermelon )
?>

From the above example we can see that after using the array_diff function, the "banana" element is removed from the array is deleted, and the index values ​​of other elements in the array remain unchanged.

Summary

This article introduces three commonly used methods in PHP to remove an element from an array. They are using the unset function, array_splice function and array_diff function. It should be noted that after using these methods, the index values ​​of other elements in the array may change, so you need to pay attention to maintaining the order and continuity of the index when processing the array.

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