How to delete array elements in php (code example)

In PHP, array is a very common data type, and we often encounter situations where we need to delete array elements. PHP provides several different methods to delete array elements, and this article will introduce these methods.

1. unset function

The unset function in PHP can be used to delete specified elements in an array. Its syntax is as follows:

unset($array[key]);

Among them, $array is the array of elements to be deleted, and key represents the key of the element to be deleted. For example, if we want to delete the element with the key "foo" in the array $arr, we can write it like this:

unset($arr['foo']);

Note that the unset function will only delete the specified element and will not rebuild the index of the array. This means that if an element in the array is deleted, the elements following it will retain the original index value instead of rearranging the index in order.

2. array_splice function

The array_splice function in PHP can delete a specified element in an array and replace it with an element in another array. Its syntax is as follows:

array_splice($array, $offset, $length, $replacement);

Among them, $array is the array of elements to be deleted, $offset is the starting position of deletion, $length is the number of elements to be deleted, and $replacement is the array of elements to be replaced. . For example, if we want to delete two elements starting from the second position in the array $arr, we can write:

array_splice($arr, 1, 2);

This will delete the two elements $arr[1] and $arr[2]. And other elements will rearrange their index values. If we want to replace the deleted element, we can continue to pass in the $replacement parameter. For example, we have an array $replacementArr. To replace the elements in $arr with it, you can write:

$replacementArr = array('bar', 'baz');
array_splice($arr, 1, 2, $replacementArr);

This will replace the two elements $arr[1] and $arr[2]. Replaced with elements in $replacementArr.

3. array_filter function

The array_filter function in PHP can filter elements in the array through a callback function, and can also be used to delete elements in the array. Its syntax is as follows:

array_filter($array, $callback);

Among them, $array is the array of elements to be filtered (delete), and $callback is the callback function used to filter (delete) elements. The processing of elements in the callback function determines whether they are filtered (deleted).

For example, if we want to delete the elements less than 3 in the array $arr, we can write:

$arr = array(1, 2, 3, 4, 5);
$arr = array_filter($arr, function($elem) {
    return $elem >= 3;
});

This will delete the elements less than 3 in the array. Finally, the value of $arr is array (3, 4, 5).

4. array_diff function

The array_diff function in PHP can be used to compare the differences between two arrays and return the different elements. With this function, we can also delete elements from the array. Its syntax is as follows:

array_diff($array1, $array2);

Among them, $array1 and $array2 are the two arrays to be compared. This function compares all elements in $array1 with $array2 and returns elements that appear in $array1 but not in $array2.

For example, if we want to delete all elements in the array $arr that also appear in $removeArr, we can write:

$arr = array(1, 2, 3, 4, 5);
$removeArr = array(2, 4, 6);
$arr = array_diff($arr, $removeArr);

This will delete all elements in the array that also appear in $removeArr Elements, ultimately, the value of $arr is array(1, 3, 5).

To sum up, PHP provides a variety of methods to delete elements in an array, and we can choose the most suitable method according to actual needs. At the same time, it should be noted that deleting elements in the array will change the index and length of the array. It is necessary to avoid incorrect results caused by operating array elements in a loop.

The above is the detailed content of How to delete array elements in php (code example). For more information, please follow other related articles on the PHP Chinese website!