New functions in PHP8: practical application methods of array_key_last()

With the release of PHP8, some new functions have also been introduced. One of the useful new functions is array_key_last(). This article will introduce the practical application of this new function.

What is the array_key_last() function?

array_key_last() function is a new function for PHP arrays. What this function does is very simple: it returns the last key in the array. In PHP7.3 and earlier versions, to get the last key in the array, you need to use the end() function to get the last value, and the key() function to get the last key. However, this method is not very intuitive, so PHP8 introduced this new function.

The syntax of this function is as follows:

array_key_last(array $array): mixed

Parameters$array is an array to return the last key.

This function returns the last key of the array. If the array is empty, the function returns null.

The following is a simple example:

$arr = array('a' => 1, 'b' => 2, 'c' => 3, 'd' => 4);
$last_key = array_key_last($arr);
echo $last_key; // 输出：d

Actual application method

1. Delete the last element of the array

Use array_key_last( ) function can easily delete the last element of an array. Here is an example:

$fruits = array('apple', 'banana', 'cherry', 'date');
$last_key = array_key_last($fruits);
unset($fruits[$last_key]);
print_r($fruits); // 输出：Array ( [0] => apple [1] => banana [2] => cherry )

2. Add an element after the last element of the array

You can also add an element after the last element of the array using the array_key_last() function element. Here is an example:

$names = array('John', 'Mary', 'Tom');
$last_key = array_key_last($names);
$names[$last_key + 1] = 'Lisa';
print_r($names); // 输出：Array ( [0] => John [1] => Mary [2] => Tom [3] => Lisa )

3. Check whether the last element exists in the array

Sometimes you need to check whether the last element exists in an array, use the array_key_last() function Can be achieved easily. Here is an example:

$numbers = array(1, 2, 3);
$last_key = array_key_last($numbers);

if(isset($numbers[$last_key])) {
    echo '数组中存在最后一个元素';
} else {
    echo '数组中不存在最后一个元素';
}

Summary

array_key_last() function is a very useful new function in PHP8. Use this to easily get the last key of an array, which is very useful for manipulating arrays. This article introduces the syntax and practical application method of the array_key_last() function, hoping to be helpful to readers.

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