RegEx Validation - Invalidate [email protected] but validates other email

Question

I do have this regex that validates email addresses: ^\w+(\.\w+)*@(\w+\.)+\w{2,4}$

What I need is to append this current regex that will invalidate email addresses starting with none@ OR na@

How to? Thanks!

Note that your regex does not validate all valid email addresses, and rejects many valid addressses. There's more information in the answers to [How to validate an email address using a regular expression?](https://stackoverflow.com/a/201378/43452) — Stobor, Jul 23 '18 at 04:13
You may need to use grouping on the local part (the part before @) — Ṃųỻịgǻňạcểơửṩ, Jul 23 '18 at 04:21

score 2 · Accepted Answer · answered Jul 23 '18 at 04:04

2

Add negative lookahead to the beginning of the pattern:

^(?!none@|na@)\w+(\.\w+)*@(\w+\.)+\w{2,4}$

answered Jul 23 '18 at 04:04

can u please explain a little what is +\w{2,4} accounting for at the end – Inder Jul 23 '18 at 04:16
2

That was in the original pattern, so I'm assuming that's already matching what OP is looking for - a word character after a dot, repeated 2 to 4 times. For example, `[email protected]` (repeat 3x) is matched, but `[email protected]` (repeat 1x) wouldn't be, nor would `[email protected]` (repeat 5x) – CertainPerformance Jul 23 '18 at 04:19
1

@Inder It's a bad `tld` validation. Would return false for `mobile` and other new TLDs. (I also dont think a TLD can have an underscore so `[a-z\d]` would be more accurate) – user3783243 Jul 23 '18 at 04:50

1 Answers1