I am trying to get this Regex statement to work
^([_a-z0-9-]+(\.[_a-z0-9-]+)*#[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})+(\s?[,]\s?|$))+$
for a string of comma separated emails in a textbox using jQuery('#textbox').val(); which passes the values into the Regex statement to find errors for a string like:
"test#test.com, test1#test.com,test2#test.com"
But for some reason it is returning an error. I tried running it through http://regexpal.com/ but i'm unsure ?
NB: This is just a basic client-side test. I validate emails via the MailClass on the server-side using .NET4.0 - so don't jump down my throat re-this. The aim here is to eliminate simple errors.
Escaped Version:
^([_a-z0-9-]+(\\.[_a-z0-9-]+)*#[a-z0-9-]+(\\.[a-z0-9-]+)*(\\.[a-z]{2,3})+(\\s?[,]\\s?|$))+$
You can greatly simplify things by first splitting on commas, as Pablo said, then repeatedly applying the regex to validate each individual email. You can also then point out the one that's bad -- but there's a big caveat to that.
Take a look at the regex in the article Comparing E-mail Address Validating Regular Expressions. There's another even better regex that I couldn't find just now, but the point is a correct regex for checking email is incredibly complicated, because the rules for a valid email address as specified in the RFC are incredibly complicated.
In yours, this part (\.[a-z]{2,3})+ jumped out at me; the two-or-three-letters group {2,3} I often see as an attempt to validate the top-level domain, but (1) your regex allows one or more of these groups and (2) you will exclude valid email addresses from domains such as .info or .museum (Many sites reject my .us address because they thought only 3 letter domains were legal.)
My advice to reject seriously invalid addresses, while leaving the final validation to the server, is to allow basically (anything)#(anything).(anything) -- check only for an "at" and a "dot", and of course allow multiple dots.
EDIT: Example for "simple" regex
[^#]+#[^.]+(\.[^.]+)+
This matches
test#test.com
test1#test.com
test2#test.com
foo#bar.baz.co.uk
myname#modern.museum
And doesn't match foo#this....that
Note: Even this will reject some valid email addresses, because anything is allowed on the left of the # - even another # - if it's all escaped properly. But I've never seen that in 25 years of using email in Real Life.
Related
I am relatively new to using Regular Expressions with JavaScript and come across a particular situation with regards to the '#' username pattern that has given me about 3 hours of trouble.
I would like to replicate the #username pattern found on social media text fields on websites such as Facebook and Twitter. (I understand that they parse tokenized macros but I would like a pure RegEx version).
I have attached an image of the closest pattern that I have achieved, however I will also type this in order to make it easier for anyone to copy and paste into their own RegEx pattern checker.
As you can see, the # symbol aught to catch all subsequent alpha characters and nothing preceding that # symbol and be terminated by a space. There is a special case where a URL that contains an # symbol should be ignored. (As illustrated in the image) and the # symbol could be used at the very start of the textfield and in this case the handle should be parsed.
Clearly, my existing pattern is collecting the preceding character to the # symbol which is incorrect. Any help would be fantastic.
RegEx101 example (with highlights)
RegEx that is not working
/(^^|[^\/])(#[A-Za-z0-9_.]{3,25})/gm
Text version for copy+paste convenience
#test testing
#test testing
testing ,#test
https://youtube.com/#test
I tried multiple combinations of patterns, over 3 hours, to try to isolate #handle style tags as seen in popular social networks. I expected to be able to isolate only the portion of the patter that contain a single # deliminated username. I expected that I could ignore this patter where it is part of a URL.
My actual results cause the preceding character to be collected and added to the final string which is incorrect.
It sounds like you want a positive lookbehind
(?<=YOUR_REGEX)
/(?<=^|[^\/])(#[A-Za-z0-9_.]{3,25})/gm
I see you've already accepted an answer, but here's another version that may work for what you're trying to do.
/(?<=[^\/]|^)#[A-Za-z0-9_.]{3,25}/g
This matches anything that...
Is at the start of the line OR is not preceeded by a forwards slash (/)
Credit to #Samathingamajig for pointing that out.
Starts with an # symbol
Is followed by between 3 and 25 alphanumeric (incl. _ and .) characters.
I need to validate certain email addresses on the client side before the server side, they are limited to 3 domains, so for example
email#me.com
email#you.com
email#us.com
It can contain the standard combo of letters, numbers, underscore, hyphen, period etc before the # but the key requirement being "me.com", "you.com" or "us.com".
I'm shocking at regexes and have been at http://gskinner.com/RegExr/ for about 30mins but cant get anywhere close...
Any help is greatly appreciated.
Thanks
Just find any email regex, take the part before the #, and replace the part after it with
(me|you|us)\.com$
I have been researching a regular expression for the better part of about six hours today. For the life of me, I can not figure it out. I have tried what feels like about a hundred different approaches to no avail. Any help is greatly appreciated!
The basic rules:
1 - Exclude these characters in the address portion (before the # symbol): "()<>#,;:\[]*&^%$#!{}/"
2 - The address can contain a ".", but not two in a row.
I have an elegant solution to the rule number one, however, rule number two is killing me! Here is what I have so far. (I'm only including the portion up to the # sign to keep it simple). Also, it is important to note that this regular expression is being used in JavaScript, so no conditional IF is allowed.
/^[^()<>#,;:\\[\]*&^%$#!{}//]+$/
First of all, I would suggest you always choose what characters you want to allow instead of the opposite, you never know what dangerous characters you might miss.
Secondly, this is the regular expression I always use for validating emails and it works perfectly. Hope it helps you out.
/^[A-Z0-9._%+-]+#[A-Z0-9.-]+\.[A-Z]{2,6}$/i
Rule number 2
/^(?:\.?[^.])+\.?$/
which means any number of sequences of (an optional dot followed by a mandatory non dot) with an optional dot at the end.
Consider four two character sequences
xx matches as two non dot characters.
.x matches as an optional dot followed by a non-dot.
x. matches as a non-dot followed by an optional dot at the end.
.. does not match because there is no non-dot after the first dot.
One thing to remember about email addresses is that dots can appear in tricky places
"..#"#.example.com
is a valid email address.
The "..#" is a perfectly valid quoted local-part production, and .example.com is just a way of saying example.com but resolved against the root DNS instead of using a host search path. example.com might resolve to example.com.myintranet.com if myintranet.com is on the host search path but .example.com always resolves to the absolute host example.com.
First of all, to your specifications:
^(?![\s\S]*\.\.)[^()<>#,;:\\[\]*&^%$#!{}/]#.*$
It's just your regex with (?!.*\.\.) tacked onto the front. That's a negative lookahead, which doesn't match if there are any two consecutive periods anywhere in the string.
Properly matching email addresses is quite a bit harder, however.
I am using the below regex in JavaScript for password policy check:
^.*(?=.{8,})(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[##$_])(?=.*[\d\W]).*$
I tried the above regex using online regex checker
http://www.nvcc.edu/home/drodgers/ceu/resources/test_regexp.asp
Test cases passed as expected, negative test cases failed. But same regex when deployed in application does not validate properly.
For eg:
Tracker#123 does not work, where tRacker#123 works
Asd56544#12 also works fine.
Can you please point out what's wrong in regex above?
My advice is to separate this regex into several simple regex'es.
You may assign rules for your password, and for every rule you can assign a regex.
For example
Rule №1. Minimal length of password = 8 characters (can be done without regex)
Rule №2. At least one digit is required. ( /[0-9]/ )
Rule №3. At least one letter is required ( /[a-z]/i)
Rule №4. Illegal characters for password ( regex for some characters you don't want users to use in passwords)
Rule №n - some little regex
(and so on)
With this approach, it will be more easier to manage your validation in sooner time. For example after a year, you'll have to change your password policy. You'll forget what your big regex is meaning (and will spend a lot of time changing that big regex, or doing a new one). But with little separates regexes (meaning rules) you easily configure your password policy
Are you sure you syntax is correct?
Have a look at this JSfiddle, in it all the test cases pass
http://jsfiddle.net/pCLpX/
I'm using the following for email validation:
var filter = /^(\w+)(\.\w+)*#(\w+)(\.\w+)+$/;
Just noticed that it does not support xxxx+wildcard#gmail.com (it does not support the +wildcard part). Any way to get that added?
You should use \S+#\S+\.\S+, which will match anything with an # and a ..
Anything more than that will reject valid but obscure addresses.
Even this will reject valid but obscure addresses, such as "Test Me"#localhost.
However, these are never used in practice. [citation needed]
I liked SLak's answer. I actually have a regular expression I wrote awhile back that's even more open-ended.
^.+#.+\..+$
The idea behind it is similar. Don't try so hard. Instead, err on the side of accepting too much. To my knowledge this regex should accept every conceivable valid email address (and some invalid ones as well).