How to amend strings of system time?

[jess84]

Hi,

So I'm looking at time limited objects that expire in my game.

I'm storing the System Time and Date as a string. How do I modify a specific part of that to generate a new string - the expiry date time?

E.g. I want to add 10mins to the original string, which I then do a string compare to to check it's still valid.

Or is string compare expensive and I should do it completely differently?

Thanks in advance

[jess84]

I found this custom action:
http://hutonggames.com/playmakerforum/index.php?topic=1047.0

This seems to similar to what I need. Would anyone with the skills be able to amend it to output a new string based on the duration entered by a user?