Introduction to how to use the array_splice() function in the PHP function library

In PHP, arrays are one of the most commonly used data types. In order to conveniently operate arrays, PHP provides many array-related built-in functions, including the array_splice() function. The function of array_splice() function is to delete or replace array elements and return the array of deleted elements.

Now, let us learn more about how to use the array_splice() function.

Usage

The syntax of the array_splice() function is as follows:

array_splice(array &$input, int $offset [, int $length [, mixed $replacement ]] ): array

Parameters:

• &$input: Required, the array to be operated on.
• $offset: Required, the starting position of the element to be deleted or replaced. If it is a negative number, it means counting from the end of the array.
• $length: Optional, the length of the deleted element. The default is 0, which means the element will not be deleted.
• $replacement: Optional, replacement element, which can be one or more elements. If not specified, it defaults to null.

Return value:

array_splice() function returns an array composed of deleted elements.

Example:

The following code demonstrates how to use the array_splice() function:

$arr = ['first', 'second', 'third', 'forth'];
$removed = array_splice($arr, 1, 2, ['new', 'elems']); // 删除第二个和第三个元素，同时添加两个新元素
print_r($arr); // 输出 ['first', 'new', 'elems', 'forth']
print_r($removed); // 输出 ['second', 'third']

The above code first defines an array $arr containing 4 elements, and then uses array_splice The () function deletes the second and third elements in the $array array, replaces them with two new elements, and finally outputs the deleted array and the deleted element array.

Notes

When using the array_splice() function, there are several things to pay attention to:

• &$The input parameter is a reference, inside the function Modifications to it are reflected in the original array.
• If the $length parameter is a negative number, it means to delete the elements at the end of the array.
• If the $replacement parameter is not specified, the array_splice() function will only delete elements and will not return any deleted elements.
• The $replacement parameter can be a list of elements given in the form of an array, or it can be an array.
• When elements are deleted, the array index will be reordered.

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