Given the string CN=Smith\, John,OU=Users,OU=IT,DC=contoso,DC=com, I am seeking to match the complete common name, including the comma after it. I'm really trying to remove this part, so matching the other part would work too.
The result after removal or filter ought to be OU=Users,OU=IT,DC=contoso,DC=com.
I tried ^.+(?=,OU=) with no flags but this captures CN=Some\, Guy,OU=Users
The language/regex standard is PowerShell, but I can figure out the conversion from another standard, so any solution is likely better than where I am.
You can try this: ^.+?(?=,OU=), and it shell match the entire string until the OU part.
Related
I'm trying to see if its possible to extend an existing arbitrary regex by prepending or appending another regex to match within matches.
Take the following example:
The original regex is cat|car|bat so matching output is
cat
car
bat
I want to add to this regex and output only matches that start with 'ca',
cat
car
I specifically don't want to interpret a whole regex, which could be quite a long operation and then change its internal content to match produce the output as in:
^ca[tr]
or run the original regex and then the second one over the results. I'm taking the original regex as an argument in python but want to 'prefilter' the matches by adding the additional code.
This is probably a slight abuse of regex, but I'm still interested if it's possible. I have tried what I know of subgroups and the following examples but they're not giving me what I need.
Things I've tried:
^ca(cat|car|bat)
(?<=ca(cat|car|bat))
(?<=^ca(cat|car|bat))
It may not be possible but I'm interested in what any regex gurus think. I'm also interested if there is some way of doing this positionally if the length of the initial output is known.
A slightly more realistic example of the inital query might be [a-z]{4} but if I create (?<=^ca([a-z]{4})) it matches against 6 letter strings starting with ca, not 4 letter.
Thanks for any solutions and/or opinions on it.
EDIT: See solution including #Nick's contribution below. The tool I was testing this with (exrex) seems to have a slight bug that, following the examples given, would create matches 6 characters long.
You were not far off with what you tried, only you don't need a lookbehind, but rather a lookahead assertion, and a parenthesis was misplaced. The right thing is: Put the original pattern in parentheses, and prepend (?=ca):
(?=ca)(cat|car|bat)
(?=ca)([a-z]{4})
In the second example (without | alternative), the parentheses around the original pattern wouldn't be required.
Ok, thanks to #Armali I've come to the conclusion that (?=ca)(^[a-z]{4}$) works (see https://regexr.com/3f4vo). However, I'm trying this with the great exrex tool to attempt to produce matching strings, and it's producing matches that are 6 characters long rather than 4. This may be a limitation of exrex rather than the regex, which seems to work in other cases.
See #Nick's comment.
I've also raised an issue on the exrex GitHub for this.
I have this regex for email validation (assume only x#y.com, abc#defghi.org, something#anotherhting.edu are valid)
/^[a-zA-Z0-9]+#[a-zA-Z0-9]\.(com)|(edu)|(org)$/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)
Is it possible to concatenate the results of Regex Pattern Matching using only Regex syntax?
The specific instance is a program is allowing regex syntax to pull info from a file, but I would like it to pull from several portions and concatenate the results.
For instance:
Input string: 1234567890
Desired result string: 2389
Regex Pattern match: (?<=1).+(?=4)%%(?<=7).+(?=0)
Where %% represents some form of concatenation syntax. Using starting and ending with syntax is important since I know the field names but not the values of the field.
Does a keyword that functions like %% exist? Is there a more clever way to do this? Must the code be changed to allow multiple regex inputs, automatically concatenating?
Again, the pieces to be concatenated may be far apart with unknown characters in between. All that is known is the information surrounding the substrings.
2011-08-08 edit: The program is written in C#, but changing the code is a major undertaking compared to finding a regex-based solution.
Without knowing exactly what you want to match and what language you're using, it's impossible to give you an exact answer. However, the usual way to approach something like this is to use grouping.
In C#:
string pattern = #"(?<=1)(.+)(?=4).+(?<=7)(.+)(?=0)";
Match m = Regex.Match(input, pattern);
string result = m.Groups[0] + m.Groups[1];
The same approach can be applied to many other languages as well.
Edit
If you are not able to change the code, then there's no way to accomplish what you want. The reason is that in C#, the regex string itself doesn't have any power over the output. To change the result, you'd have to either change the called method of the Regex class or do some additional work afterwards. As it is, the method called most likely just returns either a Match object or a list of matching objects, neither of which will do what you want, regardless of the input regex string.
I am working with legacy systems at the moment, and a lot of work involves breaking up delimited strings and testing against certain rules.
With this string, how could I return "Active" in a back reference and search terms, stopping when it hits the first caret (^)?:
Active^20080505^900^LT^100
Can it be done with an inclusion in the regex of this "(.+)" ? The reason I ask is that the actual regex "(.+)" is defined in a database as cutting up these messages and their associated rules can be set from a front-end system. The content could be anything ('Active' in this case), that's why ".+" has been used in this case.
Rule: The caret sign cannot feature between the brackets, as that would result with it being stored in the database field too, and it is defined elsewhere in another system field.
If you have a better suggestion than "(.+)" will be happy to hear it.
Thanks in advance.
(.+?)\^
Should grab up to the first ^
If you have to include (.+) w/o modifications you could use this:
(.+?)\^(.+)
The first backreference will still be the correct one and you can ignore the second.
A regex is really overkill here.
Just take the first n characters of the string where n is the position of the first caret.
Pseudo code:
InputString.Left(InputString.IndexOf("^"))
^([^\^]+)
That should work if your RE library doesn't support non-greediness.