php array delete function

PHP is a powerful open source scripting language that is widely used in back-end development of websites and applications. In PHP, an array is a common data structure used to store a set of related data. Operating on arrays is one of the essential tasks when writing PHP programs. In an array, deleting elements is one of the common operations. This article will introduce some array deletion functions in PHP.

1. unset function

The unset function is one of the most commonly used array deletion functions in PHP. Its function is to delete the specified array element. When using the unset function, you need to pass the key name of the array element to be deleted as a parameter. If the deleted element does not exist, the unset function will fail silently.

The following is an example of using the unset function to delete array elements:

$fruits = array("apple", "banana", "cherry");
unset($fruits[1]);
print_r($fruits);

The output result is:

Array
(
    [0] => apple
    [2] => cherry
)

As shown in the above example, by passing the key parameter 1, the unset function Removed "banana" element from array.

It should be noted that after using the unset function to delete elements, the key names in the array will be rearranged. For example, in the above example, the second element is deleted and the key name of the third element is changed to 1.

2. array_splice function

array_splice function is another way to implement array deletion in PHP. Its function is to delete array elements within the specified range and return the value of the deleted element. The array_splice function needs to pass three parameters. The first parameter is the array to be operated on, the second parameter is the position to start deletion, and the third parameter is the number of elements to be deleted. If the third argument is omitted, all elements from the start to the end of the array will be removed.

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

$fruits = array("apple", "banana", "cherry");
$removed = array_splice($fruits, 1, 1);
print_r($fruits);
print_r($removed);

The output result is:

Array
(
    [0] => apple
    [1] => cherry
)
Array
(
    [0] => banana
)

As shown in the above example, using the array_splice function to delete the " banana" element and save it as the return value in the variable $removed.

It should be noted that after the array_splice function deletes elements, the key names of the original array will not be rearranged.

3. array_diff function

array_diff function is another array deletion function in PHP. Its function is to delete the first array that is the same as one or more other arrays. Elements. The array_diff function requires passing two or more arrays as parameters, and the elements in each array are considered elements to be deleted.

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

$fruits = array("apple", "banana", "cherry");
$removed = array_diff($fruits, array("banana"));
print_r($removed);

The output result is:

Array
(
    [0] => apple
    [2] => cherry
)

As shown in the above example, using the array_diff function to delete the " banana" element and save the result in the variable $removed.

It should be noted that the array_diff function returns a new array without modifying the original array.

Summary

This article introduces three common array deletion functions in PHP: unset, array_splice and array_diff. Each function has its unique uses, advantages and disadvantages, and programmers can choose the appropriate function to perform array deletion operations based on the needs of the project. No matter which function you choose, you need to understand the usage of function parameters and the type of return value to ensure the correctness and efficiency of the program.

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