Simple regex pattern for email

Question

I've been trying to work this out for almost an hour now, and I can't see myself getting much further with it without any help or explanation. I've used regex before, but only ones that are very simple or had already been made.

This time, I'm trying to work out how to write a regex that achieves the following:

Email address must contain one @ character and at least one dot (.) at least one position after the @ character.

So far, this is all I've been able to work out, and it still matches email addresses that, for example, have more than one @ symbol.

.*?@?[^@]*\.+.*

It would be helpful if you can show me how to construct a regular expression that checks for a single @ and at least one full stop one or more spaces after the @. If you could break down the regex and explain what each bit does, that would be really helpful.

I want to keep it simple for now, so it doesn't have to be a full-on super-accurate email validation expression.

Are you planning on using this in production? Why no "full-on super-accurate email validation"? — Luca Kiebel, May 14 '18 at 12:19
Possible duplicate of [How to validate an email address using a regular expression?](https://stackoverflow.com/questions/201323/how-to-validate-an-email-address-using-a-regular-expression) — Máté Safranka, May 14 '18 at 12:20
Probably [this one](https://stackoverflow.com/a/1931322/3832970) can give you a hint. — Wiktor Stribiżew, May 14 '18 at 12:21
@Luca No, I'm not. It's part of a small JavaScript project for practice. I want to keep the validation simple so I can learn regex more easily. — Dog Lover, May 14 '18 at 12:21
use this link.. will help you creating regex.. https://regexr.com/ — Himanshu Bansal, May 14 '18 at 12:22
I'd also take a look at [this answer](https://stackoverflow.com/a/32686261/6634591) — Luca Kiebel, May 14 '18 at 12:22
This satisfies your requirement: `[^@]+@[^@]+\.[^@]+` (and it adds the requirement of at least one character before the `@` and one between the `@` and the `.`). — SamWhan, May 14 '18 at 12:43

score 14 · Accepted Answer · answered May 15 '18 at 05:40

With the help of ClasG's comment, I now have a fairly straightforward and suitable regex for my problem. For the sake of anyone learning regex who might come across this question in the future, I'll break the expression down below.

Expression: ^[^@]+@[^@]+\.[^@]+$

^ Matches the beginning of the string (or line if multiline)
[^@] Match any character that is not in this set (i.e. not "@")
+ Match one or more of this
@ Match "@" character
[^@] Match any character that is not in this set
+ Match one or more
\. Match "." (full stop) character (backslash escapes the full stop)
[^@] Match any character that is not in this set
+ Match one or more
$ Matches the end of the string (or line if multiline)

And in plain language:

Start at beginning of string or line
Include all characters except @ until the @ sign
Include the @ sign
Include all characters except @ after the @ sign until the full stop
Include all characters except @ after the full stop
Stop at the end of the string or line

Based on this approach, if you need to support comma separated emails, you can use `^[^@]+@[^@]+\.[^@]+(;[^@]+@[^@]+\.[^@]+)*$`. Note that these regexes also validate emails in format `Name Lastname ` (not in a *smart way*, but because it's a simple regex). It would validate invalid stuff like `ads.com`, but that's probably acceptable because you just want to make sure the user doesn't enter total garbage or something like a phone by mistake. — Andrew, Jun 17 '22 at 04:46

score 5 · Answer 2 · edited Oct 07 '21 at 08:46

Email address must contain one @ character

No they don't. An email address with no '@' character is perfectly valid. An email address with multiple '@' characters before an IP address is perfectly valid (as long as all but 1 are outside the ADDR_SPEC or are quoted/escaped within the mailbox name).

I suspect you're not trying to validate an email address but rather an ADDR_SPEC. The answer linked by Máté Safranka describes how to validate an ADDR_SPEC (not an email address). Unless you expect to be validating records which don't have a valid internet MX record, and more than one '@' is more likely be a typo than a valid address....

/[a-z0-9\._%+!$&*=^|~#%'`?{}/\-]+@([a-z0-9\-]+\.){1,}([a-z]{2,16})/

Zombievirus · Answer 3 · 2022-11-11T17:15:49.537

0

^[^\W_]+\w*(?:[.-]\w*)*[^\W_]+@[^\W_]+(?:[.-]?\w*[^\W_]+)*(?:\.[^\W_]{2,})$

edited Nov 11 '22 at 17:15

answered Nov 10 '22 at 22:12

Zombievirus

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This fails for `-1@example.com` – Wai Ha Lee Nov 11 '22 at 08:16
I updated the Regex. This one should cover the most basic cases. – Zombievirus Nov 11 '22 at 17:16

Simple regex pattern for email

3 Answers3