How to compare dates in PHP

php_date_compareHow to actually compare 2 dates in PHP with each other? The question sounds easier than it is.  The first thought that usually comes is the following. We store both dates as strings and compare them.
Preliminary

<?php
$date1 = "2012-1-12";
$date2 = "2011-10-12";

if ($date1 > $date2)
echo "$date1 is newer than $date2";
else
echo "$date1 is older than $date2";
?>

Output:

2012-1-12 is newer than 2011-10-12

At first glance this seems to be a workable solution. But what if the two data is in a different format?

<?php
$date1 = "12-1-12";
$date2 = "2011-10-12";

if ($date1 > $date2)
echo "$date1 is newer than $date2";
else
echo "$date1 is older than $date2";
?>

Output:

12-1-12 is older than 2011-10-12

Now the date in 2012 is declared to be older than the date in 2011, which is of course wrong. However, from PHP’s point of view, this behavior is correct, because two […]

How to make simple syntax hightlighter in PHP

PHP SyntaxhighlighterIn the following article I will show you how you can write your own syntax highlighter with a few lines of PHP. By use of the following PHP snippet you can easily display PHP code on your homepage.
The whole thing is much more easily than you think. Most of the work is done by an internal PHP function named highlight_file. This function reads a file and formats the source code in color. We then merely have to count the lines of the file and output the line numbers, as well as preformat the font.
Since the snippet is not that long, I think the comments in the snippet itself are sufficient. If you still have any questions, just write a comment.

<?php
function highlight_sourcecode($file)
{
//Count the lines of the input file
$amount_of_lines = count(file($file));

//Create a list with all line numbers
$list_linenumbers = range(1, $amount_of_lines);

//Format line numbers […]