PHP function introduction: filesize() function

PHP function introduction: filesize() function

Overview:
In PHP development, we often need to obtain file size information, and PHP provides a Convenience function for this purpose - the filesize() function. The filesize() function is used to obtain the size of the specified file, and the return value is the size of the file (in bytes). This article will introduce the usage of filesize() function in detail and provide specific code examples.

Usage:
The filesize() function is very simple to use. The following is its basic syntax:

filesize(string $filename): int|false

Among them, the $filename parameter specifies the file path to obtain the size. The function returns the size of the file, or false on failure.

Code Example:
Here is an actual code example that shows how to use the filesize() function to get the size of a file:

$filename = 'file.txt';

// 检查文件是否存在
if (file_exists($filename)) {
    $filesize = filesize($filename);
    echo '文件 ' . $filename . ' 的大小为 ' . $filesize . ' 字节。';
} else {
    echo '文件 ' . $filename . ' 不存在。';
}

In the above example, we first specify To get the file path of the size, use the file_exists() function to check if the file exists. If the file exists, obtain the file size through the filesize() function and print the result. If the file does not exist, the corresponding error message is printed.

Note:
When using the filesize() function, you need to pay attention to the following points:

1. The filesize() function is only used to obtain the size of local files and is not supported. Get the size of network files.
2. To get the size of a network file, it can be achieved through other methods, such as using the cURL library or sending an HTTP HEAD request.
3. The file size is in bytes. To convert it to a more user-friendly format (such as KB, MB), you can do it with some simple calculations.

Conclusion:
The filesize() function is a convenient function in PHP for obtaining the file size. It provides a simple method to obtain file size information, which facilitates file operations during our development. Through the introduction of this article, I believe that everyone has a clearer understanding of how to use the filesize() function, and can use it flexibly in actual development. Hope this article is helpful to everyone!

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