How to remove null values ​​from php array

In PHP, array is a very commonly used data type, which can store multiple values ​​and facilitate traversal and operation. However, in actual development, we often encounter situations where arrays contain null values. These null values ​​will bring inconvenience to our program and cause errors when performing certain operations. Therefore, we need to learn how to remove null values ​​from php arrays.

1. What is a null value php array?

In PHP, null values ​​refer to NULL, false, 0, '' (empty string) and unassigned elements in the array. Therefore, a null php array is when the array contains null values.

For example, the following array $arr contains empty values ​​such as NULL, false, 0 and ''.

$arr = array('apple', NULL, 'banana', false, 0, '', 'orange');

2. How to remove null values ​​from php array?

In PHP, you can use the array_filter() function to remove empty php arrays. The array_filter() function can filter array elements using a custom function or callback function. When using this function, array elements that are false, NULL, 0, or the empty string'' will be deleted.

The following is a simple code example:

$arr = array('apple', NULL, 'banana', false, 0, '', 'orange');
$new_arr = array_filter($arr);
print_r($new_arr);

Output result:

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

As you can see, the $new_arr array only contains non-empty elements.

3. Use custom functions to remove empty value php arrays

In addition to using the array_filter() function, we can also use custom functions to remove empty value php arrays. The following is a sample code using a custom function:

function removeEmptyElement($arr){
    foreach($arr as $key => $value){
        if(empty($value)){
            unset($arr[$key]);
        }
    }
    return $arr;
}

$arr = array('apple', NULL, 'banana', false, 0, '', 'orange');
$new_arr = removeEmptyElement($arr);
print_r($new_arr);

Output result:

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

As you can see, through the custom function removeEmptyElement(), we also successfully removed all elements in the array NULL value.

4. Conclusion

In actual development, it is very common to encounter empty php arrays. This article explains how to use the array_filter() function and custom functions to remove null values ​​from php arrays. I hope this article can help PHP programmers solve practical problems and improve programming efficiency.

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