How to delete key-value pairs in an array in php

In PHP development, arrays are one of the essential data types. Sometimes we need to delete certain key-value pairs and corresponding values ​​from the array. PHP provides several different functions to delete key-value pairs in an array. In this article, we will introduce ways to delete key-value pairs in an array in PHP.

1. Use the unset() function

The unset() function is one of the most basic methods in PHP. It can completely delete a variable, including a key in the array. value pair. When deleting key-value pairs in the array, we only need to use the unset() function to reference the key to be deleted in the array. The following is a sample code that uses the unset() function to delete a key-value pair in an array:

$fruits = array("apple" => "red", "banana" => "yellow", "orange" => "orange");
unset($fruits["banana"]);

In the above example, we used the unset() function and the array subscript reference to delete $fruits A key-value pair in the array, the result will be to delete the key-value pair "banana" => "yellow".

2. Use the array_splice() function

The array_splice() function is also one of the methods used to delete key-value pairs in PHP arrays. It deletes an element from an array and inserts a value to fill the deleted position. When deleting a key-value pair, we only need to put the corresponding key into the first parameter of the function. The following is an example code for using the array_splice() function to delete a key-value pair in an array:

$fruits = array("apple" => "red", "banana" => "yellow", "orange" => "orange");
array_splice($fruits, array_search("banana", array_keys($fruits)), 1);

In the above example, we used the array_splice() function, and first used the array_keys() function to obtain $fruits All the keys in the array, then use the array_search() function to locate the position of the "banana" key in the array, and finally use the array_splice() function to delete it.

3. Using the array_filter() function

The array_filter() function can be used to delete certain key-value pairs in the array. It is implemented through a callback function, which is passed each key-value pair in the array in turn. If the return value is true, the key-value pair is retained, otherwise it is deleted. The following is an example code that uses the array_filter() function to delete a key-value pair in an array:

$fruits = array("apple" => "red", "banana" => "yellow", "orange" => "orange");
$new_fruits = array_filter($fruits, function($key) { return $key != "banana" });

In the above example, we use the array_filter() function and an anonymous function callback to remove the " banana" key-value pair is deleted from the $new_fruits array.

4. Use the unset() function combined with a loop

If you want to delete multiple key-value pairs in an array, the simplest way is to use a loop structure for each key Delete value pairs. As shown below:

$fruits = array("apple" => "red", "banana" => "yellow", "orange" => "orange");
$keys = array("banana", "orange");
foreach($keys as $key) {
    unset($fruits[$key]);
}

In the above example, we store the keys of the key-value pairs to be deleted in an array, and then use a loop structure to reference each key-value pair and use the unset() function Delete it.

Summary

There are many ways to delete array key-value pairs in PHP, including using the unset() function, array_splice() function, array_filter() function, and using unset in combination with loops () function and other methods. No matter which method is used, it can effectively delete specific key-value pairs in the PHP array. When deleting key-value pairs in an array, you also need to keep in mind the nature of the array index to ensure that the operation is correct.

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