I used to create a test case related a US SSN text field data validation, there is a Regex(Regexp or Regular Expression):
"^(?!000)([0-6]\d{2}|7([0-6]\d|7[012]))([ -]?)(?!00)\d\d\3(?!0000)\d{4}$"
which defined the input validation, I figured it out at the beginning, but after one month later when look back the documentation, there is only “!@#$%%^” in my head.
And here is a very cool site (http://www.regexper.com/) could transfer the Regex to a much easier understandable graphic chart like this:
Image may be NSFW.
Clik here to view.
Cool
Update: forgot to mention, the expression need to be in JavaScript style
Image may be NSFW.
Clik here to view.
Image may be NSFW.Clik here to view.
