How to remove a key from an array in php

In PHP programs, arrays are one of the commonly used data types, and we often need to operate on arrays. Sometimes, we need to delete a key in an array. This article teaches you how to delete a key in an array in PHP.

To delete a key in an array, you need to use the PHP built-in function unset(). The function of unset() function is to destroy a variable, including a key in the array. Its syntax is as follows:

unset($array[$key]);

Among them, $array is the array of keys to be deleted, and $key is the key to be deleted.

Next, we will introduce in detail how to delete a key in an array in PHP through the following steps.

Step 1: Create an array

First, we need to create an array, which can be created using array literals or array functions.

// 使用数组字面量创建一个数组
$arr = ['a' => 1, 'b' => 2, 'c' => 3];

// 使用数组函数创建一个数组
$arr2 = array('a' => 1, 'b' => 2, 'c' => 3);

Here we use two methods to create two arrays, one using array literals and the other using array functions. Their results are the same.

Step 2: Use the unset() function to delete a key

After we have the array, we can use the unset() function to delete a key in the array.

// 删除数组$arr中的键a
unset($arr['a']);

// 删除数组$arr2中的键b
unset($arr2['b']);

Here we use the unset() function to delete key a in array $arr and key b in array $arr2.

Step 3: Use the print_r() function to output the array

After completing the deletion operation, we can use the print_r() function to output the array to verify whether the operation just performed success.

// 输出数组$arr
print_r($arr);

// 输出数组$arr2
print_r($arr2);

The output results are as follows:

// 删除键a之后的数组$arr
Array ( [b] => 2 [c] => 3 )

// 删除键b之后的数组$arr2
Array ( [a] => 1 [c] => 3 )

As can be seen from the output results, the key we specified has been successfully deleted from the array.

Summary

Using the unset() function can very conveniently delete a key in a PHP array. It should be noted that when we delete a key, PHP will reconstruct the array, and the index will start counting from 0 according to natural numbers.

Hope this article will be helpful to PHP programmers.

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