How to remove null values ​​​​in an array in php

php method to remove empty values ​​​​in an array: 1. Use the array_filter() function to determine whether the array element is empty through a callback function. If the callback function returns true, the elements will be retained in the new array; Otherwise, it is removed; 2. Use a foreach loop to traverse the array and remove null values ​​by judging whether the element is empty; 3. Use the array_diff() function to compare the original array with an array containing only null values Compare to get an array filtered with null values.

The operating environment of this tutorial: windows10 system, php8.1.3 version, DELL G3 computer.

In PHP development, we often need to handle array operations. One of the common operations is to remove null values ​​​​from the array. Null values ​​may be caused by user input, database queries, or other operations. This article will introduce several methods to remove null values ​​​​in arrays.

Method 1: Use the array_filter() function

The array_filter() function can filter out the null values ​​​​in the array and return a new array. It uses a callback function to determine whether the array element is empty. If the callback function returns true, the element is retained in the new array; otherwise, it is removed. The following is a sample code that uses the array_filter() function to remove null values ​​​​in an array:

$array = array("apple", "", "banana", null, "cherry", 0, "date");
$filteredArray = array_filter($array, function($value) {
return $value !== '' && $value !== null;
});
print_r($filteredArray);
?>

The output result is:

Array ( [0] => apple [2] => banana [4] => cherry [6] => date 
)

In the above code, the callback function determines whether the array element is An empty string or null to determine whether the element remains in the new array.

Method 2: Use foreach loop

We can also use foreach loop to traverse the array and remove null values ​​by determining whether the element is empty. The following is a sample code that uses a foreach loop to remove null values ​​​​in an array:

$array = array("apple", "", "banana", null, "cherry", 0, "date");
$filteredArray = array();
foreach($array as $value) {
if($value !== '' && $value !== null) {
$filteredArray[] = $value;
}
}
print_r($filteredArray);
?>

The output result is:

Array ( [0] => apple [2] => banana [4] => cherry [6] => date 
)

In the above code, we create an empty array $filteredArray, and then Use a foreach loop to iterate over the original array $array. If the element is not empty, the element is added to the new array $filteredArray.

Method 3: Use array_diff() function

The array_diff() function is used to calculate the difference set of arrays. We can compare the original array with an array containing only null values ​​to get a null-filtered array. The following is an example code that uses the array_diff() function to remove null values ​​​​in an array:

$array = array("apple", "", "banana", null, "cherry", 0, "date");
$emptyArray = array("", null);
$filteredArray = array_diff($array, $emptyArray);
print_r($filteredArray);
?>

The output result is:

Array ( [0] => apple [2] => banana [4] => cherry [6] => date 
)

In the above code, we create an array that only contains null values The array $emptyArray, and then use the array_diff() function to calculate the difference between the original array $array and $emptyArray, thereby obtaining the array $filteredArray with filtered null values.

Summary

This article introduces three methods to remove null values ​​​​in PHP arrays. Whether you choose to use the array_filter() function, foreach loop or array_diff() function, you can filter null values ​​in the array. Choosing appropriate methods to operate arrays based on actual needs can improve code readability and performance efficiency. .

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