RegEx for email with only one special character-CodePudding

I am trying to modify a regex for emails (gmail) that should contains special characters like _% -. but only one, not more

I made 2 test cases below that are both passing

I also tried [a-z0-9] . [a-z0-9] instead of [A-Z0-9_% -.] but both test cases are passing

CodePudding user response：

As mentioned in the comments, you can try with

/^[A-Z0-9] (?:[_% .-][A-Z0-9] )?@[A-Z0-9.-] \.[A-Z]{2,4}$/i

/^[A-Z0-9] [_% .-][A-Z0-9] @[A-Z0-9.-] \.[A-Z]{2,4}$/i

(if there must be at least three chars before @ with . in the middle only). Try to give us more test cases to check your requirements, you can check here.

CodePudding user response：

Try using this regex:

^[^@_\% \-\.] [^@][^@_\% \-\.] @[A-Za-z\.] $

Explanation:

^: begin of string
[^@_\% \-\.] : any character other than @ or special character (_% -.)
[^@]: any character other than @ (here will match the special character, if present)
[^@_\% \-\.] : any character other than @ or special character (_% -.)
@: @
[A-Za-z\.] : any combination of alphabetical character and dot
$: end of string

Try it here.

Note: the considered special characters are the one you listed in your problem statement. If there are further special characters, you just need to add them inside explained part 2 and 4.

CodePudding user response：

This should meet your need (some may be invalid in format): ^[a-z0-9]*[_% \-.][a-z0-9]*...

If there must be characters surrounding those special chars (valid in format): ^[a-z0-9] [_% \-.][a-z0-9] ...