I'm using to validate the format of names in my rails applications. I need to update it so it doesn't accept something like mike.jones
current regex
/([A-Za-z ',.-]+)/
acceptable names
'Baxter',
'Doe de Sour Jr.',
'Smith-Brown',
"Mathias d'Arras",
"d'Arras",
'King, Jr.',
'Cotton III'
invalid names
'Baxter2',
'user#gmail',
'#michael',
'tina.fay'
The answer is a bit complicated when you need to account for periods that occur in the middle of valid names. According to your description, the rule seems to be that periods are fine as long as they aren't immediately followed by letters. This can be accomplished with regex lookahead:
^(?!.*\.\S)[A-Za-z ',.-]+$
demo: https://regex101.com/r/LkUl38/2
Then you just need to move the . to the end of your regex (and escape it) so that you still get people with Jr. at the end of their name:
/([A-Za-z ',-]+\.?)/
And it should work fine. Try it online!
There are some great resources online for learning Regex, if you're interested.
Related
I'm new to regex. I need to find instances of example.com in an .SQL file in Notepad++ without those instances being part of subdomain.example.com(edited)
From this answer, I've tried using ^((?!subdomain))\.example\.com$, but this does not work.
I tested this in Notepad++ and # https://regex101.com/r/kS1nQ4/1 but it doesn't work.
Help appreciated.
Simple
^example\.com$
with g,m,i switches will work for you.
https://regex101.com/r/sJ5fE9/1
If the matching should be done somewhere in the middle of the string you can use negative look behind to check that there is no dot before:
(?<!\.)example\.com
https://regex101.com/r/sJ5fE9/2
Without access to example text, it's a bit hard to guess what you really need, but the regular expression
(^|\s)example\.com\>
will find example.com where it is preceded by nothing or by whitespace, and followed by a word boundary. (You could still get a false match on example.com.pk because the period is a word boundary. Provide better examples in your question if you want better answers.)
If you specifically want to use a lookaround, the neative lookahead you used (as the name implies) specifies what the regex should not match at this point. So (?!subdomain\.)example trivially matches always, because example is not subdomain. -- the negative lookahead can't not be true.
You might be better served by a lookbehind:
(?<!subdomain\.)example\.com
Demo: https://regex101.com/r/kS1nQ4/3
Here's a solution that takes into account the protocols/prefixes,
/^(www\.)?(http:\/\/www\.)?(https:\/\/www\.)?example\.com$/
My college asked my to provide him with a regex that only matches if the test-string endswith
.rar or .part1.rar or part01.rar or part001.rar (and so on).
Should match:
foo.part1.rar
xyz.part01.rar
archive.rar
part3_is_the_best.rar
Should not match:
foo.r61
bar.part03.rar
test.sfv
I immediately came up with the regex \.(part0*1\.)?rar$. But this does match for bar.part03.rar.
Next I tried to add a negative look behind assertion: .*(?<!part\d*)\.(part\0*1\.)?rar$ That didn't work either, because look around assertions need to be fixed width.
Then I tried using a regex-conditional. But that didn't work either.
So my question: Can this even be solved by using pure regex?
An answer should either contain a link to regex101.com providing a working solution, or explain why it can't work by using pure regex.
You could use lookahead to verify the one case that fails your original regex (.rar with .part part that isn't 0*1) is discredited:
^(?!.*\.part0*[^1]\.rar$).*\.(part0*1\.)?rar$
See it in action
This is an old question, but here's another approach:
(?:\.part0*1\.rar|^(?<!\.)\w+\.rar)$
The idea is to match either:
A string that ends with .part0*1.rar (ie foo.part01.rar, foo.part1.rar, bar.part001.rar), OR
A string that ends with .rar and doesn't contain any other dots (.) before that.
Works on all your test cases, plus your extra foo.part19.rar.
https://regex101.com/r/EyHhmo/2
I have this regex for email validation (assume only x#y.com, abc#defghi.org, something#anotherhting.edu are valid)
/^[a-zA-Z0-9]+#[a-zA-Z0-9]\.(com)|(edu)|(org)$/i
But #abc.edu and abc#xyz.eduorg are both valid as to the regex above. Can anyone explain why that is?
My approach:
there should be at least one character or number before #
then there comes #
there should be at least one character or number after # and before .
the string should end with either edu, com, or org.
Try this
/^[a-zA-Z0-9]+#[a-zA-Z0-9]+\.(com|edu|org)$/i
and it should become clear - you need to group those alternatives, otherwise you can match any string that has 'edu' in it, or any string that ends with org. To put it another way, your version matches any of these patterns
^[a-zA-Z0-9]+#[a-zA-Z0-9]\.(com)
(edu)
(org)$
It's worth pointing out that the original poster is using this as a regex learning exercise. This would be a terrible regex for actual production use! It's a thorny problem - see Using a regular expression to validate an email address for a lot more depth.
Your grouping parentheses are incorrect:
/^[a-zA-Z0-9]+#[a-zA-Z0-9]+\.(com|edu|org)$/i
Can also just use one case as you're using the i modifier:
/^[a-z0-9]+#[a-z0-9]+\.(com|edu|org)$/i
N.B. you were also missing a + from the second set, I assume this was just a typo...
What you have written is the equivalent of matching something that:
Begins with [a-zA-Z0-9]+#[a-zA-Z0-9].com
contains edu
or ends with org
What you were looking for was:
/^[a-z0-9]+#[a-z0-9]+\.(com|edu|org)$/i
Your regex looks ok.
I guess you are looking using a find function in stead of a match function
Without specifying what you use it is a bit difficult, but in Python you would write
import re
pattern = re.compile ('^[a-zA-Z0-9]+#[a-zA-Z0-9]\.(com)|(edu)|(org)$')
re.match('#abc.edu') # fails, use this to validate an input
re.search('#abc.edu') # matches, finds the edu
Try to use it:
[a-zA-Z0-9]+#[a-zA-Z0-9]+.(com|edu|org)+$
U forget about + modificator if u want to catch any combinations of (com|edu|org)
Upd: as i see second [a-zA-Z0-9] u missed + too
I need to build a RegEx expression which gets its text strings from the Title field of my Database. I.e. the complete strings being searched are: Mr. or Ms. or Dr. or Sr. etc.
Unfortunately this field was a free field and anything could be written into it. e.g.: M. ; A ; CFO etc.
The expression needs to match on everything except: Mr. ; Ms. ; Dr. ; Sr. (NOTE: The list is a bit longer but for simplicity I keep it short.)
WHAT I HAVE TRIED SO FAR:
This is what I am using successfully on on another field:
^(?!(VIP)$).* (This will match every string except "VIP")
I rewrote that expression to look like this:
^(?!(Mr.|Ms.|Dr.|Sr.)$).*
Unfortunately this did not work. I assume this is because because of the "." (dot) is a reserved symbol in RegEx and needs special handling.
I also tried:
^(?!(Mr\.|Ms\.|Dr\.|Sr\.)$).*
But no luck as well.
I looked around in the forum and tested some other solutions but could not find any which works for me.
I would like to know how I can build my formula to search the complete (short) string and matches everything except "Mr." etc. Any help is appreciated!
Note: My Question might seem unusual and seems to have many open ends and possible errors. However the rest of my application is handling those open ends. Please trust me with this.
If you want your string simply to not start with one of those prefixes, then do this:
^(?!([MDS]r|Ms)\.).*$
The above simply ensures that the beginning of the string (^) is not followed by one of your listed prefixes. (You shouldn't even need the .*$ but this is in case you're using some engine that requires a complete match.)
If you want your string to not have those prefixes anywhere, then do:
^(.(?!([MDS]r|Ms)\.))*$
The above ensures that every character (.) is not followed by one of your listed prefixes, to the end (so the $ is necessary in this one).
I just read that your list of prefixes may be longer, so let me expand for you to add:
^(.(?!(Mr|Ms|Dr|Sr)\.))*$
You say entirely of the prefixes? Then just do this:
^(?!Mr|Ms|Dr|Sr)\.$
And if you want to make the dot conditional:
^(?!Mr|Ms|Dr|Sr)\.?$
^
Through this | we can define any number prefix pattern which we gonna match with string.
var pattern = /^(Mrs.|Mr.|Ms.|Dr.|Er.).?[A-z]$/;
var str = "Mrs.Panchal";
console.log(str.match(pattern));
this may do it
/(?!.*?(?:^|\W)(?:(?:Dr|Mr|Mrs|Ms|Sr|Jr)\.?|Miss|Phd|\+|&)(?:\W|$))^.*$/i
from that page I mentioned
Rather than trying to construct a regex that matches anything except Mr., Ms., etc., it would be easier (if your application allows it) to write a regex that matches only those strings:
/^(Mr|Ms|Dr|Sr)\.$/
and just swap the logic for handling matching vs non-matching strings.
re.sub(r'^([MmDdSs][RSrs]{1,2}|[Mm]iss)\.{0,1} ','',name)
I'm being lazy tonight and don't want to figure this one out. I need a regex to match 'jeremy.miller' and 'scottgu' from the following inputs:
http://codebetter.com/blogs/jeremy.miller/archive/2009/08/26/talking-about-storyteller-and-executable-requirements-on-elegant-code.aspx
http://weblogs.asp.net/scottgu/archive/2009/08/25/clean-web-config-files-vs-2010-and-net-4-0-series.aspx
Ideas?
Edit
Chris Lutz did a great job of meeting the requirements above. What if these were the inputs so you couldn't use 'archive' in the regex?
http://codebetter.com/blogs/jeremy.miller/
http://weblogs.asp.net/scottgu/
Would this be what you're looking for?
'/([^/]+)/archive/'
Captures the piece before "archive" in both cases. Depending on regex flavor you'll need to escape the /s for it to work. As an alternative, if you don't want to match the archive part, you could use a lookahead, but I don't like lookaheads, and it's easier to match a lot and just capture the parts you need (in my opinion), so if you prefer to use a lookahead to verify that the next part is archive, you can write one yourself.
EDIT: As you update your question, my idea of what you want is becoming fuzzier. If you want a new regex to match the second cases, you can just pluck the appropriate part off the end, with the same / conditions as before:
'/([^/]+)/$'
If you specifically want either the text jeremy.miller or scottgu, regardless of where they occur in a URL, but only as "words" in the URL (i.e. not scottgu2), try this, once again with the / caveat:
'/(jeremy\.miller|scottgu)/'
As yet a third alternative, if you want the field after the domain name, unless that field is "blogs", it's going to get hairy, especially with the / caveat:
'http://[^/]+/(?:blogs/)?([^/]+)/'
This will match the domain name, an optional blogs field, and then the desired field. The (?:) syntax is a non-capturing group, which means it's just like regular parenthesis, but won't capture the value, so the only value captured is the value you want. (?:) has a risk of varying depending on your particular regex flavor. I don't know what language you're asking for, but I predominantly use Perl, so this regex should pretty much do it if you're using PCRE. If you're using something different, look into non-capturing groups.
Wow. That's a lot of talking about regexes. I need to shut up and post already.
Try this one:
/\/([\w\.]+)\/archive/