Detailed explanation of how to obtain file size in PHP (with video)

This article mainly introduces to you the specific methods of PHP to obtain the file size and encapsulation to obtain the normal size.

For those new to PHP, it may be difficult to implement the function of getting the file size in PHP. However, I believe that novices will be able to easily master the important knowledge of obtaining file size with PHP after reading the introduction in this article!

Below we use specific code examples to provide you with a detailed analysis of PHP's method of obtaining the file size.

1. First, if you only need to get the number of bytes of the file

You can get it directly through the PHP filesize function, the code is as follows:

echo filesize("upload.php");

Accessed through a browser, the output result is as follows:

As you can see from the above picture Yes, the file size we directly output is 1614 bytes, and the file size seen in the upload.php attribute is also 1614 bytes. We all know the file size. In addition to being expressed in bytes, it is more commonly expressed in units such as KB, MB, GB, and TB.

2. So if we want to get the file size and display it in a normal size format, how should we do it?

Below we introduce a very simple encapsulation method to obtain the normal size.

The specific code example of the PHP encapsulation method to obtain the normal size is as follows:

<?php
$size = filesize("upload.php");
function trans_byte($byte)
{
    $KB = 1024;
    $MB = 1024 * $KB;
    $GB = 1024 * $MB;
    $TB = 1024 * $GB;
    if ($byte < $KB) {
        return $byte . "B";
    } elseif ($byte < $MB) {
        return round($byte / $KB, 2) . "KB";
    } elseif ($byte < $GB) {
        return round($byte / $MB, 2) . "MB";
    } elseif ($byte < $TB) {
        return round($byte / $GB, 2) . "GB";
    } else {
        return round($byte / $TB, 2) . "TB";
    }
}
echo trans_byte($size);

In this code, we first define a $size variable to obtain upload.php The byte size of the file, and then create a method named filesize. This method is used to convert the byte size into a normal size format.

Everyone should know that computer counting uses binary, which is calculated by powers of 2. 1KB=2 to the 10th power=1024B; 1MB=2 to the 20th power=1024*1024B=1024KB; GB, TB conversion and so on.

So in the filesize method, we first define the four variables $KB, $MB, $GB, and $TB in the above code. Then use if...elseif conditional statements to gradually determine the file byte size, and use the PHP round function to retain two decimal places on the file size value.

Then we test the above encapsulated filesize method to obtain the normal size of the file, and access php through the browser to obtain the file size The result is as follows:

As you can see from the above figure, we can already achieve it through our own encapsulated filesize methodphp calculates the file sizeand successfully obtains it File normal size function. Some friends may have discovered that the obtained size is not exactly the same as the size of the file's own attributes. In fact, it is very normal to have a slight error when obtaining the size through the PHP method and can be ignored.

Then the above is a detailed explanation of the PHP method of obtaining file size and an introduction to the encapsulation method of converting file byte acquisition into KB, MB, GB, TB formats, that is, normal size display! This article also has a corresponding Video tutorial for everyone to learn and refer to [PHP method of obtaining file byte size and encapsulating normal size], which is very easy to understand. I hope it will be helpful to friends in need. There is some help!

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