How to delete the value of an array in php? Share in multiple ways

Deleting values ​​from an array is a common task in PHP programming because arrays are usually one- or two-dimensional data structures that store multiple values. Also, sometimes during code execution, it is necessary to delete certain elements from the array to update or modify the contents of the array.

In PHP, there are many ways to delete array values. This article will introduce some of the most common methods.

1. Use the unset() function

The unset() function can be used to delete or release variables. In PHP, you can delete elements in an array through the unset() function, or you can delete the entire array.

For example, suppose there is the following array:

$fruits = array('apple', 'banana', 'pear', 'orange');

We can use the unset() function to delete an element in it:

unset($fruits[1]);

This will delete the array with index Element of 1, i.e. 'banana'.

If you want to delete the entire array, you can use the following code:

unset($fruits);

2. Use array_splice() function

array_splice() Functions are one of the very useful functions in PHP. It can perform insertion and deletion operations on arrays. When deleting array elements, we can set the number of elements to be deleted with the second parameter of the array_splice() function.

For example, continuing with the array above:

$fruits = array('apple', 'banana', 'pear', 'orange');

If you want to remove the second element in the array, you can use the following code:

array_splice($fruits, 1, 1);

This will remove it from the array The element with index 1, which is 'banana'.

array_splice() function has other uses, such as inserting a new element after deleting an element, replacing old elements, etc.

3. Using the array_filter() function

The array_filter() function is a function used for array filtering in PHP. Use this function to filter the elements in the array according to certain conditions and return elements that meet the conditions.

For example, suppose we have the following array:

$fruits = array('apple', 'banana', 'pear', 'orange');

We can use the array_filter() function to filter out an element in the array. The following code removes the element that meets the criteria, which is 'banana':

$fruits = array_filter($fruits, function($value) {
    return $value !== 'banana';
});

This code will test the value of each element in the array through the callback function, and if the value of the element is not equal to 'banana', then keep it element. The filtered array is as follows:

array('apple', 'pear', 'orange');

4. Use the unset() and array_values() functions

The above three methods can delete the array elements, but may cause some problems. When an array element is deleted using the unset() function or the array_splice() function, the index of the array will change accordingly. This means that we cannot guarantee the continuity of array indexes.

In order to solve this problem, we can use the unset() function to delete the array elements, and then use the array_values() function to re-index the array to ensure the continuity of the array index. The following is a sample code:

$fruits = array('apple', 'banana', 'pear', 'orange');

// 删除索引为 1 的元素（即 'banana'）
unset($fruits[1]);

// 重新索引数组
$fruits = array_values($fruits);

The above code sets the value of the new array to the value of the original array, but the index has been reordered and its continuity is guaranteed.

Summary

In PHP, there are multiple ways to delete elements from an array. Using the unset() function and array_splice() function are the two most common methods. The array_filter() function can filter out elements in an array based on conditions and return a new array. If you need to maintain the continuity of array indexes, you can use a combination of unset() and array_values() functions to accomplish the task.

No matter which method is used, be sure to ensure that there are no problems with the index of the array after deleting the array elements.

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