What is the purpose of the urldecode function in PHP?

In PHP, the urldecode() function is used to decode a string that has been encoded using URL encoding. URL encoding is a method of converting special characters into %xx format for passing parameters or data in a URL.

The urldecode() function decodes %xx encoded strings back to their original characters. It can be used to decode URL parameters passed through a get request or decode URL-encoded form data passed through a POST request.

For example, when passing parameters through a URL, special characters like spaces will be encoded as %20. By using the urldecode() function, %20 can be decoded back to a space, allowing PHP to properly handle and display these parameters.

原文：他在工作中总是迟到，以致于经理已经开始注意到了。

Paraphrase: He is always late for work, to the point that the manager has started to take notice.

$url = "https://example.com/search?q=hello%20world";

// 解码URL参数
$query = parse_url($url, PHP_URL_QUERY);
$decodedQuery = urldecode($query);

echo $decodedQuery;  // 输出: hello world

When dealing with URL encoded data, it is usually necessary to use the urldecode() function to decode it into its original characters for proper handling and display.