How to get uploaded file size in php

For new PHP users, 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!

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Below we will give you a detailed analysis and introduction through specific code examples. How to get file size in PHP.

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");

Access through the browser, the output result is as follows:

As you can see from the above figure, the file size we obtain by direct output is 1614 bytes, while in upload. The file size seen in the php properties is 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 the byte size of the upload.php file. Then create a method named filesize, which 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. Access php through the browser to obtain the file size. The result is as shown below:

From above As can be seen from the figure, through our own encapsulated filesize method, we can already realize the function of PHP calculating the file size and successfully obtaining the normal size of the file. 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 method of obtaining the file size in PHP and an introduction to the encapsulation method of converting the file byte acquisition into KB, MB, GB, and TB formats, that is, normal size display! It's very easy to understand. I hope it will be helpful to friends in need!

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