How to clear empty value array elements in php

During the PHP development process, it is often necessary to remove empty elements in the array to reduce the length of the array and improve program efficiency. This article will introduce methods and techniques for clearing array null values ​​in PHP, and give examples.

1. Use the array_filter() function to filter array empty values

The array_filter() function is a function in PHP specifically used to filter arrays. We can use this function to filter the elements in the array and remove empty elements in the array.

Sample code:

$arr = array("name" => "张三", "age" => "", "sex" => "男", "address" => "", "email" => "zhangsan@example.com");
$arr = array_filter($arr); // 过滤掉数组中的空值
print_r($arr);

Output result:

Array
(
    [name] => 张三
    [sex] => 男
    [email] => zhangsan@example.com
)

In the above sample code, we first define an array $arr, which contains several elements, including The value of some elements is empty. Then we called the array_filter() function to filter the array, and finally got a new array that did not contain any null values.

At the same time, we can also use the array_filter() function to filter the specified elements in the array. For example, we only want to filter the age and address elements in the array, which can be achieved using the following sample code:

$arr = array("name" => "张三", "age" => "", "sex" => "男", "address" => "", "email" => "zhangsan@example.com");
$arr = array_filter($arr, function($value, $key) {
    return ($key == 'age' || $key == 'address') ? false : true; // 只保留非 age 和 address 元素
}, ARRAY_FILTER_USE_BOTH);
print_r($arr);

Output results:

Array
(
    [name] => 张三
    [sex] => 男
    [email] => zhangsan@example.com
)

In the above sample code, we use array_filter () The second parameter of the function, which is the callback function. This callback function returns true or false, which is used to determine whether the array elements should be retained. We only keep non-age and address elements, filtering out the two null elements in the array.

2. Use foreach to loop through the array and delete null value elements

In addition to using the array_filter() function, we can also use foreach to loop through the array and delete the null value elements. delete.

Sample code:

$arr = array("name" => "张三", "age" => "", "sex" => "男", "address" => "", "email" => "zhangsan@example.com");
foreach ($arr as $key => $value) {
    if ($value == "") {
        unset($arr[$key]); // 删除空值元素
    }
}
print_r($arr);

Output result:

Array
(
    [name] => 张三
    [sex] => 男
    [email] => zhangsan@example.com
)

In the above sample code, we traverse the array $arr through the foreach loop, find the null value elements in it, and use unset() function to delete. We ended up with the same result as the previous example.

3. Use the array_diff() function to compare arrays to delete empty elements

In addition to the above two methods, we can also use the array_diff() function to compare arrays to delete empty elements. value element.

Sample code:

$arr = array("name" => "张三", "age" => "", "sex" => "男", "address" => "", "email" => "zhangsan@example.com");
$null_arr = array("");
$arr = array_diff($arr, $null_arr); // 从 $arr 中删除 $null_arr 中的元素
print_r($arr);

Output result:

Array
(
    [name] => 张三
    [sex] => 男
    [email] => zhangsan@example.com
)

In the above sample code, we first define an array $null_arr that only contains null values, and then use array_diff( ) function compares the arrays $arr and $null_arr, removes all elements in $null_arr from $arr, and ultimately gets the same result as the previous example.

Summary

The above introduces three methods of clearing null elements in PHP arrays, including using the array_filter() function to filter the array, using the foreach loop to traverse the array to delete elements, and using the array_diff() function. Compare arrays to delete elements. Different methods are suitable for different scenarios, and developers can choose according to the actual situation. The sample code introduced in this article can be used as a reference for developers.

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