How to delete the same key value in php array

PHP is a very popular server-side scripting language because of its ability to easily process data and provides a rich library of functions and tools so that developers can easily build complex websites and applications. One very common operation is to delete a key in an array, rather than just deleting an array element.

In PHP, the method of deleting a key in an array depends on the specific scenario, but below we will introduce three common methods.

Method 1: Use the unset() function

The easiest way is to use PHP's built-in function unset(). This function can delete the specified element in the array by passing in the key name to be deleted.

The following is an example:

<?php
$array = array("name" => "John", "age" => 30, "email" => "john@example.com");
unset($array["email"]);
print_r($array);
?>

The output is:

Array
(
    [name] => John
    [age] => 30
)

In this example, we use the unset() function to delete the "email" element in the array. Use the print_r() function to output the result of the array. You can see that the array no longer contains the deleted elements.

Method 2: Use the array_filter() function

If you want to delete multiple array elements, or want to use a reusable filter, then using the array_filter() function is more appropriate . The array_filter() function uses a custom callback function to filter array elements and delete elements that do not meet the conditions.

Here is an example:

<?php
$array = array("name" => "John", "age" => 30, "email" => "john@example.com", "phone" => "");
$array = array_filter($array, function($value) {
    return $value !== "";
});
print_r($array);
?>

The output is:

Array
(
    [name] => John
    [age] => 30
    [email] => john@example.com
)

In this example, we define a callback function that will remove all empty strings from the array Elements. We pass the $array array to the array_filter() function and it will return a new array with all empty string elements removed.

Method 3: Use the array_diff_key() function

The last method is to use the array_diff_key() function. This function will remove an element from one array at a specified key in another array.

The following is an example:

<?php
$array1 = array("name" => "John", "age" => 30, "email" => "john@example.com", "phone" => "");
$array2 = array_flip(array("email", "phone"));
$array3 = array_diff_key($array1, $array2);
print_r($array3);
?>

The output is:

Array
(
    [name] => John
    [age] => 30
)

In this example, we use the array_diff_key() function to delete "email" and "email" in the $array1 array "phone" element. We first convert the key to be deleted into a new array using the array_flip() function and then pass it to the array_diff_key() function.

Conclusion

All three methods can be used to delete a key in the array, and the specific use depends on your specific scenarios and requirements. In the case of using the unset() function to delete a single element, it is recommended to use the isset() function to check whether the key to be deleted exists to avoid accidentally deleting undefined keys.

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