Regex 101 Exercise S3 - Validate a zip+4 zip code

Exercise S3 - Validate a zip+4 zip code.

The US has a 5 digit zip code with an optional 4 digit suffix. Write a regex to validate that the input is in the proper format:

Sample strings

98008
98008-4893

I'm going to keep comments enabled in case people have questions about the exercise, but please don't post answers in the comments.

Comments

• Anonymous
  November 07, 2005
  It's amazing how some people don't read the entries all the way through. =)
  
  I was going to say, I'm getting good at this reg-ex thing. The answers are there if you look through the previous blog entries.
• Anonymous
  November 11, 2005
  An interesting one to try is a simple Email address, as defined in RFC-2822. What would seem a simple task, is quite complex. That is, for a complete definition based on the RFC.