Regular Expression for some email rules

Question

Hi,

I was using a regular expression for email formats which I thought was ok but the customer is complaining that the expression is too strict. So they have come back with the following requirement:

The email must contain an "@" symbol and end with either .xx or .xxx ie.(.nl or .com). They are happy with this to pass validation. I have started the expression to see if the string contains an "@" symbol as below

^(?=.*[@])

this seems to work but how do I add the last requirement (must end with .xx or .xxx)?

Answer 1

Try this :

([\w-\.]+)@((?:[\w]+\.)+)([a-zA-Z]{2,4})\be(\w*)s\b

A good tool to test our regular expression : http://gskinner.com/RegExr/

Answer 2

You could use

[@].+\.[a-z0-9]{2,3}$

Answer 3

A regex simply enforcing your two requirements is:

^.+@.+\.[a-zA-Z]{2,3}$

However, there are email validation libraries for most languages that will generally work better than a regex.

Answer 4

I always use this for emails

          ^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
            @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
            @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$

Try http://www.ultrapico.com/Expresso.htm as well!

Answer 5

It is not possible to validate every E-Mail Adress with RegEx but for your requirements this simple regex works. It is neither complete nor does it in any way check for errors but it exactly meets the specs:

[^@]+@.+\.\w{2,3}$

Explanation:

• [^@]+: Match one or more characters that are not @
• @: Match the @
• .+: Match one or more of any character
• \.: Match a .
• \w{2,3}: Match 2 or 3 word-characters (a-zA-Z)
• $: End of string