Regex for email validation with separator

Question

I am trying to achive regex expression: I need regex with email, I am using that:

\S+@\S+\.\S+

And I want to repreat it X times with ; separator. I cant figure this out... For example pattern should allow following strings:

[email protected]
[email protected];[email protected];[email protected];[email protected]

But should not allow for example following string:

[email protected];example2email.com;[email protected];

Please see [this](https://stackoverflow.com/questions/201323/how-can-i-validate-an-email-address-using-a-regular-expression) — captain-yossarian from Ukraine, Jun 10 '22 at 11:23

score 1 · Answer 1 · answered Jun 10 '22 at 11:18

1

In general, the X-separated list of entities is matched with ^y(?:Xy)*$ like pattern.

Here, there is a caveat related to what you match with y and X: \S matches ; chars, so the semi-colon has to be "removed" from the \S pattern, hence the \S should be replaced with [^\s;] in the resulting pattern.

You can use

^[^\s;]+@[^\s;]+\.[^\s;]+(?:;[^\s;]+@[^\s;]+\.[^\s;]+)*$

See the regex demo.

Details:

^ - start of string
[^\s;]+@[^\s;]+\.[^\s;]+ - one or more chars other than whitespace and ;, @, one or more chars other than whitespace and ;, . and then again one or more chars other than whitespace and ;
(?: - start of a non-capturing group:
- ; - a semi-colon
- [^\s;]+@[^\s;]+\.[^\s;]+ - email-like pattern (described above)
)* - end of the non-capturing group, repeat zero or more occurrences
$ - end of string.

answered Jun 10 '22 at 11:18

Wiktor Stribiżew

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Thanks! Generally works but now I can pass emails with strange character, for example: [email protected] – zxf18682 Jun 10 '22 at 11:31
@zxf18682 In the [same way](https://regex101.com/r/Fpfqin/2). – Wiktor Stribiżew Jun 10 '22 at 11:36
[email protected] should not be passed and other characters like (,),* etc. that should not contain in email – zxf18682 Jun 10 '22 at 11:58
@zxf18682 You need to define the rules for the user, domain and TLD parts of the regex. This is out of scope of the current question. There are a lot of email validation regex questions on SO, please use the site search. – Wiktor Stribiżew Jun 10 '22 at 12:03

Regex for email validation with separator

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