08c02-3.php

介绍PHP5的给类型函数应用

<?php
// A function to format the bytes of a file, as a natural looking string.
// This version handles it via 1024 based logic:
function format_bytes($bytes) {
    // Define an array of the different display forms:
    // These are the SI approved binary variations:
    $display = array('B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 
        'ZiB', 'YiB');
    
    // Now, constantly divide the value by 1024 until it is less than 1024
    $level = 0;
    while ($bytes > 1024) {
        $bytes /= 1024;
        $level++;
    }

    // Now we have our final value, format it to just 1 decimal place
    // and append on to the the appropriate level moniker.
    return round($bytes, 1) . ' ' . $display[$level];
}

// Echo out a few examples to test the function:
echo '<p>4200 bytes = ', format_bytes(4200), "<p>\n"; // 4.1 KiB
echo '<p>420000 bytes = ', format_bytes(420000), "<p>\n"; // 410.2 KiB
echo '<p>42000000 bytes = ', format_bytes(42000000), "<p>\n"; // 40.1 MiB
?>