How to remove null in array in php

In PHP, arrays are a very common data type, and in many cases we need to process arrays. However, in actual development, it is very likely that the array contains null values, and at this time we need to remove these null values. So, how do we remove null values ​​from an array in PHP? Next, this article will introduce you to several commonly used methods.

Method 1: Use the array_filter() function

array_filter() function is a very commonly used PHP function. Its function is to filter the elements in the array. You can filter the array according to your own defined filter function. elements in . We can easily use it to remove null values ​​from an array. The following is the specific implementation method:

$arr = array('apple', null, 'orange', null, 'banana');
$arr = array_filter($arr, function($v){return !is_null($v);});
print_r($arr);

In the above code, we first define an array, then use the array_filter() function to filter out the elements that meet the conditions, and assign the processed results to the initial array. Finally output the processed array. The running results are as follows:

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

As you can see, we have successfully removed the null value in the array.

Method 2: Use foreach loop

In addition to using the array_filter() function, we can also use the foreach loop to remove null values ​​​​in the array. The specific implementation method is as follows:

$arr = array('apple', null, 'orange', null, 'banana');
$newArr = array();   //定义一个新数组，存放除去null值的元素
foreach($arr as $value){
    if(!is_null($value)){    //判断是否是null值
        array_push($newArr, $value);   //将非null值插入新数组
    }
}
print_r($newArr);   //输出新数组

In the above code, we first define an initial array, and then define a new array to store elements excluding null values. Next, we use a foreach loop to iterate through each element in the initial array, and when the element is not a null value, insert it into the new array. Finally output the processed array. The running results are the same as method one.

Method 3: Use the array_diff() function

The third method to remove null values ​​​​in an array is to use the array_diff() function. By finding the difference between an array and other arrays, you can implement set operations function. Here we can generate a new array by removing nulls from the original array, and then find the difference with the original array to get an array with null values ​​removed. The following is the specific implementation method:

$arr = array('apple', null, 'orange', null, 'banana');
$newArr = array_diff($arr, array(null));   //生成新数组，并与原数组求差集
print_r($newArr);    //输出新数组

In the above code, we first define an initial array, and then use the array_diff() function to form a new array with elements that do not contain null values. Finally output the new array.

Summary

There are three ways to remove null values ​​​​in an array in PHP: using the array_filter() function, using the foreach loop and using the array_diff() function. Among them, using the array_filter() function and the foreach loop are relatively common implementation methods, while the method of using the array_diff() function is relatively simple. In specific development, we can choose the corresponding method according to actual needs.

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