REGEX

Regular expression. Thanks to Stephen Cole Kleene who introduced this concepts.

I'm not capable enough with regex, I still working on it. Hahaha.

I will post here for such common expression.

• IP

^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$

• etc.
• etc.