How to clear null values ​​in array in php

PHP is a popular server-side programming language and one of the main tools for web application development. It is easy to use, flexible and powerful. In PHP development, it is often necessary to operate arrays, and in some cases it is necessary to clear the empty values ​​​​in the array. In this case, you need to use a function to clear the empty values ​​​​in the array.

The function to clear the empty value in the array can loop through the array to determine whether the array element is empty. If it is empty, delete the element from the array. Although this method is feasible, it is cumbersome, especially for large-scale arrays, and is not efficient.

PHP provides a simpler way to clear empty values ​​in an array, using the built-in function array_filter(). The array_filter() function accepts an array as a parameter and returns a new array that only contains elements that meet the conditions.

The following is a simple sample code that demonstrates how to use the array_filter() function to clear empty elements in an array:

$arr = array("apple", "", "banana", null, "cherry");

$new_arr = array_filter($arr, function($value) { 
    return !is_null($value) && $value !== ''; 
});

print_r($new_arr);

In the above code, $arr is the original array, containing five elements, two of which are null. Using the array_filter() function, specify a callback function to check whether each element in the array is empty and return a new array.

The logic of the callback function is very simple. It first uses the is_null() function to determine whether the element is null, and then uses !=='' to determine whether the element is an empty string. Returns true if the element is not null and is not an empty string, otherwise returns false.

Finally output the new array $new_arr to the screen, run the code, and the results are as follows:

Array
(
    [0] => apple
    [2] => banana
    [4] => cherry
)

As you can see, the final $new_arr array only contains three elements, that is, except All elements except null values. This makes it easy to handle null values ​​in the original array, making the code more concise and readable.

In addition to using the callback function, the array_filter() function can also accept an optional parameter to specify whether to delete null values ​​​​in the array. If the argument is false, null values ​​will be retained in the array, otherwise they will be removed. This parameter is not specified in the above example, so null values ​​in the array are removed by default.

To sum up, using the array_filter() function can easily clear the null values ​​​​in the array without traversing the entire array. The code is more concise and easy to read, and it can also improve the operating efficiency of the code. In PHP development, rational use of built-in functions will greatly improve code quality and development efficiency.

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