How to delete array in PHP

PHP array is one of the most commonly used data structures in the development process, which can easily store and process large amounts of related data. PHP supports various array operations such as adding, modifying, and deleting elements from an array. Among them, deleting array elements is a very important operation, because it can help programmers better manage and maintain PHP code.

This article will explore the deletion operation of PHP arrays and introduce how to use PHP's built-in functions to delete elements in the array. At the same time, some other custom methods will also be introduced to help developers better manage PHP arrays.

1. Use PHP built-in function to delete array elements

1. unset() function

The unset() function in PHP is the most commonly used to delete arrays Element methods. With this function you can delete a specified element from an array. The syntax format is as follows:

unset($array_name[key]);

Here, $array_name is the name of the array to be deleted, and key is the number of the element to be deleted.

Sample code:

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

Output result:

Array ( [0] => apple [2] => cherry )

In this example, the second element 'banana' is deleted, and only the rest is left in the output result Two elements.

2. array_splice() function

The array_splice() function in PHP can also be used to delete elements from an array. This method adds or removes one or more elements from the array. The syntax format is as follows:

array_splice($array_name, $start, $length);

In this syntax, $array_name is the name of the array to be deleted. $start is the starting position, that is, where to start deleting. If $start is a positive number, calculation starts from the beginning of the array; if it is a negative number, calculation starts from the end of the array. $length is the number of elements to delete. Note that if $length is not specified, all elements starting at $start to the end of the array will be deleted.

Sample code:

$array = array('apple', 'banana', 'cherry', 'durian', 'eggplant');
array_splice($array, 1, 2);
print_r($array);

Output result:

Array ( [0] => apple [1] => durian [2] => eggplant )

In this example, starting from position 1 of the $array array, 2 elements are deleted, namely 'banana' and 'cherry'.

2. Use a custom method to delete array elements

1. Use the unset() function and foreach loop

Another way to delete array elements is Use unset() function and foreach loop. This method iterates through the array and checks whether each element meets the specified criteria. If the conditions are met, the element is removed using the unset() function.

Sample code:

$array = array('apple', 'banana', 'cherry', 'durian', 'eggplant');
foreach($array as $key=>$value) {
   if ($value == 'banana') {
      unset($array[$key]);
   }
}
print_r($array);

Output result:

Array ( [0] => apple [2] => cherry [3] => durian [4] => eggplant )

In this example, we use a foreach loop to check each element in the array. If the element's value is 'banana', use the unset() function to remove it.

2. Use the array_filter() function

Another method is to use PHP’s built-in function array_filter() function. This method can filter the array according to the specified conditions and return a new array instead of deleting the elements of the original array.

The syntax format is as follows:

array_filter($array_name, $callback);

In this syntax, $array_name is the name of the array to be processed. $callback is an optional custom function used to specify filter conditions. If not specified, all null values ​​in the array will be removed.

Sample code:

$array = array('apple', 'banana', 'cherry', '', 'durian', 'eggplant');
$new_array = array_filter($array, function($value) {  return $value !== '';});
print_r($new_array);

Output result:

Array ( [0] => apple [1] => banana [2] => cherry [4] => durian [5] => eggplant )

In this example, we use the array_filter() function to filter the array. This function filters out null values ​​and returns a new array.

Conclusion:

The above are several methods to delete PHP array elements, among which the unset() function and array_splice() function are the two most commonly used methods. Using the unset() function is the fastest and easiest way to remove a single element from an array. If you want to remove multiple elements or use other filtering conditions, you should use other methods. These methods provide a more flexible way to help you manage PHP data in a more efficient way.

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