In PHP, we often need to process array data, but sometimes there may be some null values in the array. In order to avoid the problems caused by these null values, we need to remove them.
Below, we will introduce several commonly used methods to remove null values in arrays.
The array_filter function is a very powerful function in PHP that can be used to filter elements in an array. Its optional second parameter can Used to specify the filtering method.
When using array_filter to remove empty values in the array, you can use empty in the callback function to determine whether the element is empty. If so, exclude the element.
The specific code is as follows:
$arr = array('a', '', 'b', 'c', null, 'd'); $arr = array_filter($arr, function($val) { return !empty($val); });
In the above example, the null values in the $arr array will be removed.
array_diff function is used to compare two arrays and return the difference between the two arrays. We can compare the original array with an array containing only empty elements Find the difference set, and the result is an array with null values removed.
The specific code is as follows:
$arr = array('a', '', 'b', 'c', null, 'd'); $empty_arr = array(''); $arr = array_diff($arr, $empty_arr);
In the above example, we first create a new array $empty_arr, which contains only one empty element. Then, we use the array_diff function to find the difference between $empty_arr and the original array. The result is an array with null values removed.
We can also use foreach loop to traverse the array, determine whether the element is empty, and add the non-empty elements to a new array. The resulting array is the array with null values removed.
The specific code is as follows:
$arr = array('a', '', 'b', 'c', null, 'd'); $new_arr = array(); foreach($arr as $val) { if(!empty($val)) { $new_arr[] = $val; } }
In the above example, we create a new empty array $new_arr, and then traverse the original array through a foreach loop and determine whether the element is empty. If If it is not empty, add it to $new_arr. Finally, the resulting $new_arr is the new array with null values removed.
Summary
Removing null values from arrays is very common in PHP, and the processing method is also very simple. We can use the array_filter function, array_diff function, or foreach loop to traverse the array to delete null values in the array. Just choose different ways to handle null values in the array according to the actual situation.
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