Let's say the variable $dairy = "qwerasdf". How would I set the first four digits from the right to another variable ("asdf"), for example? What about the first four digits from the left instead ("qwer")?

Thanks,
Laogeodritt

For the last four digits, it would be:
$var = substr($dairy, -4);

For the first four, it would be:
$var = substr($dairy, 0, 4);

And if you need more information on the substr function, go to: http://php.net/substr

Thanks.

There are so many functions, it's difficult to find the one you need if you have no idea what to look for exactly...