Delete php array

PHP is a programming language widely used in Web development, in which arrays are one of the most basic and commonly used data types. When developers use arrays, they sometimes need to delete the array in order to better manage the array content. This article will introduce the deletion operation of PHP arrays to make readers more familiar with the use and operation of PHP arrays.

1. Delete a single element of the array

In PHP, use the unset() function to delete a single element of the array. The example is as follows:

<?php
// 定义一个数组
$arr = array('apple', 'banana', 'watermelon', 'pear', 'peach');

// 删除数组中的第三个元素，即'watermelon'
unset($arr[2]);

// 打印输出数组
print_r($arr);
?>

The output result is:

Array ( [0] => apple [1] => banana [3] => pear [4] => peach )

By using the unset() function, you can delete a single element according to the array subscript. It should be noted that the deleted element subscripts will not be rearranged, but will remain in their original order.

2. Delete multiple elements of an array

If you need to delete multiple elements of an array in PHP, you can use the array_splice() function. This function can delete the element at the specified position in the array and replace the deleted element with a new element. The example is as follows:

<?php
// 定义一个数组
$arr = array('apple', 'banana', 'watermelon', 'pear', 'peach');

// 删除数组中的第二个到第四个元素，即'banana'、'watermelon'、'pear'
array_splice($arr, 1, 3);

// 打印输出数组
print_r($arr);
?>

The output result is:

Array ( [0] => apple [1] => peach )

By using the array_splice() function, you can delete multiple elements at the specified position in the array and replace the deleted elements with new elements. . Among them, the first parameter is the original array, the second parameter is the subscript of the starting position that needs to be deleted, and the third parameter is the number of elements that need to be deleted. It should be noted that the subscripts of deleted elements will be rearranged so that the subscripts of the array are continuous.

3. Delete multiple key values ​​in the array

In addition to deleting single or multiple elements in the array, you can also delete multiple key values ​​in the array. In PHP, this function can be achieved using the array_diff_key() function. This function can return an array that contains all key data that appears in the original array but does not exist in another array. An example is as follows:

<?php
// 定义一个数组
$arr1 = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5);
$arr2 = array('a' => 1, 'c' => 3, 'e' => 5);

// 删除数组中的多个键值，即'b'、'd'
$result = array_diff_key($arr1, $arr2);

// 打印输出结果
print_r($result);
?>

The output result is:

Array ( [b] => 2 [d] => 4 )

By using the array_diff_key() function, you can return a new array that contains all the keys in the original array that do not appear in another array value pair. It should be noted that this function can only delete key-value pairs, not individual elements.

Summary:

In PHP, array is a commonly used data type and one of the most basic data types in Web development. When working with arrays, sometimes you need to delete elements or key-value pairs in the array to better manage the data. This article introduces three common methods of deleting arrays in PHP, including deleting a single element, deleting multiple elements, and deleting multiple key-value pairs. By becoming familiar with these methods, developers can become more proficient in using PHP arrays and improve development efficiency.

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