Regex match repeating pattern

Question

I'm trying to match e-mails with a string like:

s.te.e.ve.s.mit.h.p@gmail.com

Effectively I'm after any repeating pattern (of at least 4 times) of a string of characters followed by a period, with the last before the email domain not having a period.

I'm not great with Regex, but so far I've only come up with:

[aA-zZ\.]{4,}[aA-zZ]@.*

This matches what I need, however it also pulls more than I'd like.

Any advice?

Maybe `^(?:[a-zA-Z]*\.){4}[a-zA-Z.]*@.*`? See https://regex101.com/r/Dx8yDg/1 — Wiktor Stribiżew, Oct 27 '20 at 13:20
Or `(?:[A-Za-z]+\.*){4,}@.*` https://regex101.com/r/rGL0ml/2 — G.Dimov, Oct 27 '20 at 13:28
@G.Dimov When you quantify `\.` with `*`, you remove the requirement that there must be dots in the string. — Wiktor Stribiżew, Oct 27 '20 at 13:32
`[aA-zZ]` is a dangerous thing, it will match `[\]^_\`` too. The correct form is mentioned in above comments! — vrintle, Oct 27 '20 at 13:37

score -1 · Answer 1 · answered Oct 27 '20 at 13:41

-1

Thanks for the help, I see now where I was making the mistake. Wiktor's answer seemed to work the best, though for some reason it would time out in Redshift if I didn't put . in brackets. [.]

The expression which appears to work correctly is:

^([a-zA-Z][.]){4,}[a-zA-Z]@.*

answered Oct 27 '20 at 13:41

Steve P

1

1

Correct. I was looking to match text separated by at least 4 periods, but not at the end. So there will be at least 5 groups of text separated by 4 periods. – Steve P Oct 27 '20 at 14:39

Regex match repeating pattern

1 Answers1