I am trying to build a regular expression for a specific name with optional text in the middle. This alone is fairly easy:
^(pom)(.*?)([.]xml)$
However, there is one constraint I would like to have. This may be is possible, perhaps it isn't (I haven't been able to find anything like this). There can be additional text within the file name but if it is there, it has to be preceded with an underscore. The following example should help illustrate what I am trying to get:
pom.xml - SUCCEED
pomdxml - FAIL
pomd.xml - FAIL
pom_asdf.xml - SUCCEED
pom_.xml - FAIL
Thank you in advance for your knowledge and help!
Here you go:
^(pom)(_.+)?(\.xml)$
Just use an optional group.
^(pom)(_.*)?(\.xml)$
This also worked for me
^pom(_\w+)*([.]xml)$
Related
I am trying to develop a regular expression to extract this: PT~MM:SS~EQP>G-G<EQP from a file.
PT is optional but if it is present it's only valid if it is 1P, 2P, 1EP or 2EP.
So if the example is: 3EP~101:37~POR>4-2<ISL it shouldn't be matching nothing but I am getting 2EP~101:37~POR>4-2<ISL as a match.
So far I've tried this:
(((1|2)P|(1|2)EP)~)?(0{0,1}([0-9]|[1-8][0-9]|9[0-9]|1[01][0-9]|120)):(0*([0-9]|[1-4][0-9]|5[0-9]))~[A-Z]{3}>[0-9]-[0-9]<[A-Z]{3}
Can someone help me?
This might what you are looking for ^(?:[12]E?P)?~?\w+?:\w+?~\w+?>\w-\w<\w{3} (https://regex101.com/r/T8Cy4C/6). Although you did not specified fully what are the requirements for each parts.
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 an .hgdontignore file :-) to include certain files and exclude everything else in a directory. Basically I want to include only the .jar files in a particular directory and nothing else. How can I do this? I'm not that skilled in regular expression syntax. Or can I do it with glob syntax? (I prefer that for readability)
Just as an example location, let's say I want to exclude all files under foo/bar/ except for foo/bar/*.jar.
The answer from Michael is a fine one, but another option is to just exclude:
foo/bar/**
and then manually add the .jar files. You can always add files that are excluded by an ignore rule and it overrides the ignore. You just have to remember to add any jars you create in the future.
To do this, you'll need to use this regular expression:
foo/bar/.+?\.(?!jar).+
Explanation
You are telling it what to ignore, so this expression is searching for things you don't want.
You look for any file whose name (including relative directory) includes (foo/bar/)
You then look for any characters that precede a period ( .+?\. == match one or more characters of any time until you reach the period character)
You then make sure it doesn't have the "jar" ending (?!jar) (This is called a negative look ahead
Finally you grab the ending it does have (.+)
Regular expressions are easy to mess up, so I strongly suggest that you get a tool like Regex Buddy to help you build them. It will break down a regex into plain English which really helps.
EDIT
Hey Jason S, you caught me, it does miss those files.
This corrected regex will work for every example you listed:
foo/bar/(?!.*\.jar$).+
It finds:
foo/bar/baz.txt
foo/bar/baz
foo/bar/jar
foo/bar/baz.jar.txt
foo/bar/baz.jar.
foo/bar/baz.
foo/bar/baz.txt.
But does not find
foo/bar/baz.jar
New Explanation
This says look for files in "foo/bar/" , then do not match if there are zero or more characters followed by ".jar" and then no more characters ($ means end of the line), then, if that isn't the case, match any following characters.
Anyone that wants to use negative lookaheads (or ?! in regex syntax) or any kind of back-referencing mechanism should be aware that Mercurial will fall back from google's RE2 to Python's re module for matching.
RE2 is a non-backtracking engine that guarantees a run-time linear with the size of the input. If performance is important to you, that is if you have a big repository, you should consider sticking to more simple patterns that Re2 supports, which is why I think that the solution offered by Ryan.
I'm trying to create an expression that matches anything between two whitespaces that does contain at least one - but have no f** idea how to do that.
Trying things like (?<=\s)[A-Z0-9(\-)+]+(?=\s) don't work at all...
Has anybody a good idea?
Try
(?<=\s)\S*-\S*(?=\s)
You might not even need the look ahead/behind:
\S*-\S*
may work just fine
I want to get just the filename using regex, so I've been trying simple things like
([^\.]*)
which of course work only if the filename has one extension. But if it is adfadsfads.blah.txt I just want adfadsfads.blah. How can I do this with regex?
In regards to David's question, 'why would you use regex' for this, the answer is, 'for fun.' In fact, the code I'm using is simple
length_of_ext = File.extname(filename).length
filename = filename[0,(filename.length-length_of_ext)]
but I like to learn regex whenever possible because it always comes up at Geek cocktail parties.
Try this:
(.+?)(\.[^.]*$|$)
This will:
Capture filenames that start with a dot (e.g. .logs is a file named .logs, not a file extension), which is common in Unix.
Gets everything but the last dot: foo.bar.jpeg gets you foo.bar.
Handles files with no dot: secret-letter gets you secret-letter.
Note: as commenter j_random_hacker suggested, this performs as advertised, but you might want to precede things with an anchor for readability purposes.
Everything followed by a dot followed by one or more characters that's not a dot, followed by the end-of-string:
(.+?)\.[^\.]+$
The everything-before-the-last-dot is grouped for easy retrieval.
If you aren't 100% sure every file will have an extension, try:
(.+?)(\.[^\.]+$|$)
how about 2 captures one for the end and one for the filename.
eg.
(.+?)(?:\.[^\.]*$|$)
^(.*)\\(.*)(\..*)$
Gets the Path without the last \
The file without extension
The the extension with a .
Examples:
c:\1\2\3\Books.accdb
(c:\1\2\3)(Books)(.accdb)
Does not support multiple . in file name
Does support . in file path
I realize this question is a bit outdated, however, I had some trouble finding a good source and wound up making the regex myself. To save whoever may find this time,
If you're looking for a ~standalone~ regex
This will match the extension without the dot
\w+(?![\.\w])
This will always match the file name if it has an extention
[\w\. ]+(?=[\.])
Ok, I am not sure why I would use regular expression for this. If I know for example that the string is a full filepath, then I would use another API to get the file name. Regular expressions are very powerfull but at the same time quite complex (you have just proved that by asking how to create such a simple regex). Somebody said: you had a problem that you decided to solve it using regular expressions. Now you have two problems.
Think again. If you are on .NET platform for example, then take a look at System.IO.Path class.
I used this pattern for simple search:
^\s*[^\.\W]+$
for this text:
file.ext
fileext
file.ext.ext
file.ext
fileext
It finds fileext in the second and last lines.
I applied it in a text tree view of a folder (with spaces as indents).
Just the name of the file, without path and suffix.
^.*[\\|\/](.+?)\.[^\.]+$
Try
(?<=[\\\w\d-:]*\\)([\w\d-:]*)(?=\.[\.\w\d-:]*)
Captures just the filename of any kind within an entire filepath. Purposefully excludes the file path and the file extension
Etc:
C:\Log\test\bin\fee105d1-5008-410c-be39-883e5e40a33d.pdf
Doesn't capture (C:\Log\test\bin)
Captures (fee105d1-5008-410c-be39-883e5e40a33d)
Doesn't capture (.pdf)
This RegExp works for me:
(.+(?=\..+$))|(.+[^\.])
Results (bold means match):
test.txt
test 234!.something123
.test
.test.txt
test.test2.txt
.