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

In PHP, array is a very useful data type, which allows us to combine multiple values ​​​​to find and operate easily. Sometimes, we need to delete a key-value pair (that is, a key and the corresponding value) from an existing array. In this case, we can use some of the functions that come with PHP to complete this operation.

Let’s take a look at how to delete key-value pairs in a PHP array. First, we can use the unset() function to delete the value of a specified key. Here is an example:

$fruit = array(
    'apple' => 'red',
    'banana' => 'yellow',
    'orange' => 'orange'
);

unset($fruit['banana']);

print_r($fruit);

Output:

Array (
    [apple] => red
    [orange] => orange
)

As mentioned above, we used the unset() function to delete the key-value pair with the key 'banana' in the array $fruit. When we print the $fruit array again, we can see that 'banana' is no longer in it.

Another way to delete multiple key-value pairs in an array is to use the array_diff_key() function. The array_diff_key() function compares the keys of two or more arrays and returns a new array containing the key differences. We can remove key-value pairs by merging this array with the original array. The following is an example:

$fruit = array(
    'apple' => 'red',
    'banana' => 'yellow',
    'orange' => 'orange'
);

$to_remove = array(
    'banana' => true,
    'orange' => true
);

$fruit = array_diff_key($fruit, $to_remove);

print_r($fruit);

Output:

Array (
    [apple] => red
)

In the above example, we first create a new array $to_remove, which contains the key names to be deleted. We then use the array_diff_key() function to compare the $fruit array with the $to_remove array to get a new array containing only the keys that exist in the $fruit array. Finally, we assign this new array to $fruit and complete the deletion operation.

It should be noted that using the unset() function will directly modify the original array, while using the array_diff_key() function will create a new array, so when multiple key-value pairs need to be deleted, especially for For large arrays, it is more efficient to use array_diff_key().

To summarize, there are two common ways to delete key-value pairs in PHP arrays: using the unset() function and the array_diff_key() function. When using the unset() function, you only need to specify the key name you want to delete. When using the array_diff_key() function, you need to create a new array containing the key names to be deleted, and compare the two arrays to obtain a new array to achieve deletion. It is necessary to flexibly choose different deletion methods according to the actual situation to achieve more efficient and convenient operations.

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