How to delete elements without key value in array in php

In PHP, array is a very important data structure. When developers write PHP scripts, they often need to store and process data through arrays. In PHP, we can create arrays of different types and forms, and these arrays can contain different types of values ​​such as strings, numbers, booleans, etc.

In some cases, we need to operate on an array, which may be to add, delete or modify the value of the array. One of the common operations is to delete elements from an array. In PHP, we can use the unset() function to delete elements from an array. However, the unset() function requires the key value of the element to be deleted. If an element in the array does not have a corresponding key value, the unset() function will not be able to delete the element.

To solve this problem, we can use a simple trick. We can use the array_filter() function to filter an array to remove elements without key values. The array_filter() function is a PHP built-in function that filters elements in an array based on specified rules. We can use this function to filter out elements without key values ​​to achieve the effect of deleting elements.

The following is a sample code that demonstrates how to use the array_filter() function to delete elements without key values ​​in the array:

<?php
$array = array("名字" => "小明", "年龄" => 20, "性别" => "男", "语文" => 85, "数学" => 90, "英语" => 80, "", null);

$array = array_filter($array, function($value) {
    return !empty($value);
});

print_r($array);
?>

The above code can also be used to delete elements in the array through the unset() function. Empty elements, but the array_filter() function can filter array elements more flexibly. If there are other invalid elements in the array, we can filter out other invalid elements by modifying the callback function.

It should be noted that when we use the array_filter() function, we need to provide a callback function for the second parameter. In this callback function, we need to specify a Boolean value to indicate whether to retain the array elements. If true is returned, the element is retained, otherwise it is deleted. In the sample code above, we used an anonymous function to implement this callback function.

To summarize, through the array_filter() function, we can very easily delete elements without key values ​​in the array. This method is not only simple and easy to understand, but also more flexible and can filter out other invalid elements. In actual development, we can choose different methods to delete array elements as needed.

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