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Regex: How to valid domain part not in email have all numeric

I am struggling with one issue where I need to verify domain part should not all be numeric.
For example:
abc#123.com -> Invalid
abc#1abc.com -> valid
Regex:
^(?=(.{1,64}#.{1,255}))((?!.*?[._]{2})[!#$%&'*+\-\/=?\^_`{|}~a-zA-Z0-9}]{1,64}(\.[!#$%&'*+\-\/=?\^_`{|}~a-zA-Z0-9]{0,}(?<!\.)){0,})#((\[(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}\])|((?!-)(?=.*[a-zA-Z])[a-zA-Z0-9-]{1,63}(?<!-)(\.(?!-)[a-zA-Z0-9-]{1,63}(?<!-)){1,}))$
Above regex need modification because there are some other validation which is working fine with above regex. Only thing is pending to validate domain part should not all numeric.
Updated:
After some research on above regex
I am able to segregate emails in to different groups. Now for group 10 need to add validation if all characters in group 10 string are aplha numeric.
Regex:
^(?=(.{1,64}#.{1,255}))((?!.*?[._]{2})[!#$%&'*+\-\/=?\^_`{|}~a-zA-Z0-9}]{1,64}(\.[!#$%&'*+\-\/=?\^_`{|}~a-zA-Z0-9]{0,}(?<!\.)){0,})#((\[(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)(\.(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}\])|((?!-)(?=.*[a-zA-Z])((?:.*[a-zA-Z0-9]))[a-zA-Z0-9-]{0,63}(?<!-)(\.(?!-)[a-zA-Z0-9-]{1,63}(?<!-)){1,}))$
Explore regex on : https://regex101.com/
TIA

There's no point in doing this - the fact that an email fulfills the requirements as set forth in RFC5322 does not mean it's a valid email address: The only way to know that, is to send an email to it, and have the user reply to it, follow a link inside it, or copy a code/token inside it.
Given that you have to do that anyway, that will also pick up any issues with invalid email addresses. Thus, the correct validation for email is:
Pattern.compile("^.+#.+\\..+$")
(Assuming you don't want single
and this does what you want, which is, filter out obvious incorrect entries, and that's all you need.
If you insist in continuing your mistake, there's always emailregex.com, which has the regex and explains how it works.
NB: Note that you're just wrong. 12345#678.cde can easily be valid - com may not allow you to register a domain that consists solely of digits, but it's not an inherent limitation of the DNS system: Domain parts can be all numbers. The top level domain cannot be, at least, for now, but any other part of it can be. Thus, rejecting foo#123.com is only possible if you program in, on a per-TLD basis, the exact rules. Which also means you need to sign up to the mailing list of every TLD operator to check for any changes they make. You'll be updating that regex every other week. Told you it's a silly thing to want to do!

u can use this to detect the invalid ones.
^\w+([-+.']\w+)*+#\d+.com
just change the .com to which postfix you like.

Simple email regex, make sure user includes dot domain?

I don't mess around with Regex too much but have been able to get this one online. /.+#.+/. This will return true with both joe#joe and joe#joe.com. I want to make it so a user must supply a domain extension otherwise I want it to fail, I presume this is quite simple but I just can't figure it out. I've tried /.+#.+.\S/ but that didn't work. Any help would be great, thanks!
This will be used in both PHP and javascript. The current one works in both, the new will need to also.

Here is expression
/\w+#\w+\.\w{2,10}/
to allow more characters:
/[\w\-\._]+#[\w\-\._]+\.\w{2,10}/

The regex here works for me (from http://www.regextester.com/19 )
/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+#[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/i
As does this example of regex inside JavaScript from plnkr here: http://embed.plnkr.co/ZlbA1I2TsDBUmDb9o0gj/

Given that I don't know what the rest of your code is and you might really need this for both PHP and JavaScript I will suggest a different approach as I don't agree with the solution given in the accepted answer because it will match email addresses like -#-.aa, .#.-.aa, .#_.aa etc.
I'd suggest you use PHP's filter_var with the FILTER_VALIDATE_EMAIL filter which
validates e-mail addresses against the syntax in RFC 822, with the exceptions that comments and whitespace folding and dotless domain names are not supported.
and probably an additional AJAX call from JavaScript .
Regular Expressions matching all valid email address are not trivial at all and I'm not even sure you can rely on them for matching ALL valid email addresses.
For more information please take a look at Validate email address in JavaScript? and Using a regular expression to validate an email address

.+\#.+\.{1}.+
This is a simple regex and will match the required criteria

For a simple regex that will accept any domain extension of one character or longer, try: /.+#.+\..+/
For a 2 character domain extension or longer, try: /.+#.+\..{2,}/

Regular expression for email or mobile number in one field like facebook email/mobile field in registration

Regular expression for email or mobile number in one field like facebook email/mobile field in registration
I am building a registration form in in which i am trying a make a field say email/mobile where user can either put email address or mobile number with country code.similiar approach is used in facebook registration.can anyone have solution for such regular expression. i am building the form using angularjs with its default validator.

I use this for email in python. The syntax should be the same in js
"^[\S]+#[\S]+.[\S]+$"
as far as phone number goes, there's a lot of ways it could go.
You may just want them to type 10 numbers:
[0-9]{10}
but what if they are in a place that still uses 7 numbers? or they are international (international codes are 2-3 digits)?
[0-9]{10}|[0-9]{7}|[0-9]{12,13}
but what if they decide to put hyphens in?
[0-9]{10}|[0-9]{7}|[0-9]{13}|([0-9]{2,3})?-[0-9]{3}-[0-9]{3}-[0-9]{4}
now I think we can smush this together to make something more interesting, making the hyphens optional.
^(([0-9]{2,3})-?)?([0-9]{3}-?)?[0-9]{3}-?[0-9]{4}
Lastly make sure to break your tests in a decision tree like if...else so you can get different logic for whatever the user decides to put in.
corollary:
this does match 123-4567890
as well as 123456-7890
But you might want to accept that input in good faith.

Regex for valid, and invalid email addresses

I'm looking for some regex to match valid emails (doesn't need to be some whopping RFC-compatible job) and people trying to trick the system with invalid email addresses.
Examples of things I want to catch:
blah#blah.com
blah#blah.org
blah#blah.weirdtld
blat [ AT ] blah.com
blah[at]blah.com
blah#blah[ DOT]com
blah#blah[ dot ].com
etc.
I'm sure someone out there has published a tried-and-tested expression of all known permutations, but if they have, I can't find it, and would love to see it.
I don't care if it catches domains by accident, as they are being stripped anyway.
A real-world example of what this could be used for is eBay. Seller wants to put in their description "Contact me on: bob#example.com for a cheaper price" as they would not have to pay listing fees. I want to catch that address, regardless of how it is written.
I appreciate it's impossible to check everything, and this is not a replacement for human intervention (which is also a part of the validation process already, I'm just trying to make their lives easier).
I have already searched StackOverflow and Google, but unfortunately it's one of those problems which can be difficult to search for. If anyone has a link to a solution I would be very grateful.
Edit: Just to clarify even more. This is NOT to be used to check if an email address is valid or not. This is to be used to stop people entering valid email addresses AND email addresses with common substitutions into a textarea ([at] for #, [dot] for ., (d0t) for ., and so on and so forth).

I guess if even heavy spammers haven't found an easy way to overcome this problem, you won't have much luck here, either.
there are several reasons why it's a suicidal task to think about an algorithm for this, but the main one is human creativity vs machine stupidity.
There are literally infinite ways to camouflage an email address, for example test # domain.com (remove spaces) or test[d0t]again atsign domain[.com] (it took me 2 seconds to think about them and you surely can decode them without any issue.
Even if you can list every possible alternative (which is an inhuman task, anyway), somebody else will design a different scheme to hide their email contact (example: place email address inside an inline image)
Just by comparison, here is the best regex out there to simply detect valid email addresses that covers every RFC822 case.

See: How to Find or Validate an Email Address.
Excerpt:
...there's often a trade-off between what's exact, and what's
practical.
The virtue of my regular expression above is that it matches 99% of
the email addresses in use today. All the email address it matches can
be handled by 99% of all email software out there. If you're looking
for a quick solution, you only need to read the next paragraph. If you
want to know all the trade-offs and get plenty of alternatives to
choose from, read on.
To catch expressions that are likely aliases for an email address, just do a second test for [AT], [ at ], [DOT], etc. For example, here is a RegEx that does just that (the i qualifier tells Perl to ignore case):
/\[\s*(AT|DOT)\s*\]/i

Best practices for email address validation (including the + in gmail addresses)

I know there are a lot of questions on here about email validation and specific RegEx's. I'd like to know what the best practices are for validating emails with respect to having the username+anythingelse#gmail.com trick (details here). My current RegExp for JavaScript validation is as follows, but it doesn't support the extra + in the handle:
/^([a-zA-Z0-9_.-])+#(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$/
Are there any other services that support the extra +? Should I allow a + in the address or should I alter the RegEx to only allow it for an email with gmail.com or googlemail.com as the domain? If so, what would be the altered RegEx?
UPDATE:
Thanks to everyone for pointing out that + is valid per the spec. I didn't know that and now do for the future. For those of you saying that its bad to even use a RegEx to validate it, my reason is completely based on a creative design I'm building to. Our client's design places a green check or a red X next to the email address input on blur of it. That icon indicates whether or not its a valid email address so I must use some JS to validate it then.

+ is a valid character in an email address. It doesn't matter if the domain isn't gmail.com or googlemail.com
Regexes aren't actually a very good way of validating emails, but if you just want to modify your regex to handle the plus, change it to the following:
/^([a-zA-Z0-9_.-\+])+#(([a-zA-Z0-9-])+.)+([a-zA-Z0-9]{2,4})+$/
As an example of how this regex doesn't validate against the spec: The email ..#-.com is valid according to it.

If you need to validate emails via regexp, then read the standard or at least this article.
The standard suggests to use this regexp:
(?:[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*")#(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])
If that doesn't scare you, it should :)

I would tend to go with something along the lines of /.+#.+\..+/ to check for simple mistakes. Then I would send an email to the address to verify that it actually exists, since most typos will still result in syntactically valid email addresses.

The specs allow for some really crazy ugly email addresses. I'm often very annoyed by websites even complaining about perfectly normal, valid email addresses, so please, try not to reject valid email addresses. It's better to accept some illegal addresses than to reject legal ones.
Like others have suggested, I'd go with using a simple regexp like /.+#.+/ and then sending a verification email. If it's important enough to validate, it's important enough to verify, because a legal email address can still belong to someone other than your visitor. Or contain an unintended but fatal typo.
*Edit: removed the dot from the domain part of the regex, because a#to is still a valid email address. So even my super simplified validation rejected valid addresses. Is there any downside at all to just accepting everything that contains an # with something in front and behind it?

A very good article about this subject I Knew How To Validate An Email Address Until I Read The RFC