08c02-2.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:
	$display = array('B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB');
	
	// 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 kB
echo '<p>420000 bytes = ', format_bytes(420000), "<p>\n"; // 410.2 kB
echo '<p>42000000 bytes = ', format_bytes(42000000), "<p>\n"; // 40.1 MB
?>