How to delete elements with specified subscript in php array

PHP is a very popular web development language that provides many useful functions and features, including arrays. Arrays are one of the most commonly used data types in PHP and can be used to store and manipulate large amounts of data.

Arrays are usually used as containers to store related data in PHP. When dealing with arrays, we often need to delete or modify elements at a specific index. In this article, we will discuss how to delete a specified subscript from an array in PHP.

First of all, we need to make it clear: the subscript of a PHP array can be a number or a string. If the subscript is a number, the array is called an indexed array; if the subscript is a string, the array is called an associative array. Below we will discuss how to delete specified subscript elements in index arrays and associative arrays respectively.

Delete the specified subscript element in the index array

In PHP, there are two ways to delete the specified subscript element in the index array: use the unset function or use the array_splice function. We'll cover both methods in turn.

Use the unset function to delete the specified subscript element

The unset function is one of the keywords used to destroy variables in PHP. When we use the unset function to delete an element in the array, the element and its corresponding subscript will be completely deleted, and the subscripts of other elements will also be reordered.

For example:

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

The above code will delete the banana element with index 1, and the output result is:

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

Use the array_splice function to delete the specified subscript element

## The #array_splice function is one of the functions in PHP used to delete, insert or replace array elements. It deletes a specified number of elements from the original array starting at a specified index position and replaces them with new elements. If you do not provide an element to insert or replace, the function will delete the specified element.

For example:

$fruits = array('apple', 'banana', 'cherry', 'date');
array_splice($fruits, 1, 1);
print_r($fruits);

The above code will delete the banana element with index 1, and the output result is:

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

Delete the specified subscript element in the associative array

Compared with deleting the specified subscript element in the index array, deleting the specified subscript element in the associative array is slightly more complicated. Because the subscript of an associative array is a string, you cannot use the array_splice function or the unset function like an indexed array.

In PHP, we can use the array_filter function to conveniently delete specified subscript elements in associative arrays. The array_filter function can filter elements in an array according to specified rules and return a new filtered array.

For example:

$fruits = array(
    'a' => 'apple',
    'b' => 'banana',
    'c' => 'cherry',
    'd' => 'date'
);

$fruits = array_filter($fruits, function ($key) {
    return $key !== 'b';
}, ARRAY_FILTER_USE_KEY);

print_r($fruits);

The above code will delete the banana element with the key 'b', and the output result is:

Array (
    [a] => apple
    [c] => cherry
    [d] => date
)

Summary

Delete the PHP array Specifying subscripted elements is a very common operation. When dealing with indexed arrays, we can use the unset function or array_splice function; when dealing with associative arrays, we can use the array_filter function. These functions can help us delete specified elements and update the structure of the array.

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