Using ASP.NET, and trying to implement friendly url re-writing but I'm having a heck of a time working with the regular expression. Basically, I'm checking the url directly following the domain to see whether it is using the french-canadian culture, or whether it is a number - and not a number followed by characters. I need to catch anything that begins with 'fr-ca' OR a number, and both scenarios can have a trailing '/' (forward slash), but that's all...
fr-ca - GOOD
fr-ca/ - GOOD
fr-ca/625 - GOOD
fr-ca/gd - BAD
fr-ca43/ - BAD
1234 - GOOD
1234/ - GOOD
1234/g - GOOD
1234g - BAD
1g34 - BAD
This is what I've come up with : ^(fr-ca)?/?([0-9]+)?
But it doesn't seem to be working the way I want.. so I started fresh and came up with (^fr-ca)|(^[0-9]), which still isn't working the way I want. Please...HELP!
no idea about Asp.net, but the regexp was tested with grep. you could try in your .net box:
kent$ cat a
fr-ca
fr-ca/
fr-ca/625
fr-ca/gd
fr-ca43/
1234
1234/
1234/g
1234g
1g34
updated
kent$ grep -P "(^fr-ca$|^\d+$|^(fr-ca|\d+)/(\w|\d*)$)" a
fr-ca
fr-ca/
fr-ca/625
1234
1234/
1234/g
--
well this may not be the best regex, but would be the most straightforward one.
it matchs string
^fr-ca$
or ^\d+$
or ^(fr-ca|\d+)/(\w|\d*)$
the above line can be broken down as well
^(fr-ca|\d+)/(\w|\d*)$ :
starting with fr-ca or \d+
then comes "/"
after "/" we expect \w or \d*
then $(end)
What about
^(fr-ca(?:\/\d*)?|[0-9]+(\/[a-zA-Z]*)?)$
See it here on Regexr, it matches all your good cases and not the bad ones.
Probably can try...
^(fr-ca|\d).*$
But of course this a regex to match the entire string (as it has the end-of-sting $ anchor). Are you wanting to pull out multiple matches?
In light of re-reading the post :)
^(fr-ca|\d+)(\/\d+|\/)?$
^(\d+(\/\w*)?)$|^(fr-ca\/\d+)$|^(fr-ca\/?)$
This worked for me for all of your examples. I'm not sure your intention for using this regex so I don't know if it is capturing exactly what you want to capture.
Related
I have a req to provide US Zip+4 with the +4 being optional and the +4 can't be 0000. I'm doing this in .NET therefore I'm using RegularExpressionValidator with RegEx set. In my first validator I'm checking if the Zip code is xxxxx-xxxx or xxxxx format that is 5+4 or 5. In my 2nd validator I check if the last 4 are not set to 0000. This means 1234-0000 is invalid. These are my Regex and I want to be sure they are valid. Seems they test okay, however when cross checking them with the regex101 app online I'm getting different behavior than .NET.
xxxxx-xxxx or xxxxx = ^[0-9]{5}(?:-[0-9]{4})?$
xxxxx-0000 = \d{5}(?!-0000).*
This last one I quite don't understand how it works, but it seems to work. Someone help explain me the ?! and .* they both seem to need to be necessary for this to function. My understanding is the .* means all char and the ?! means negative lookahead????
Actually, the regex pattern I would suggest here is actually a combination of the two you provided above:
^[0-9]{5}(?!-0000$)(?:-[0-9]{4})?$
Demo
Here is an explanation of the pattern:
^ from the start of the ZIP code
[0-9]{5} match a 5 digit ZIP code
(?!-0000$) then assert that the PO box is NOT -0000
(?:-[0-9]{4})? match an optional -xxxx PO box (which can't be 0000)
$ end of the ZIP code
Of note, the (?!-0000$) term is called a negative lookahead, because it looks ahead in the input and asserts that what follows is not -0000. But, using a lookahead does not advance the pattern, so after completing the negative assertion, the pattern continues trying to match an optional -xxxx PO box following.
This question already has answers here:
Regular expression to stop at first match
(9 answers)
Closed 2 years ago.
I have this gigantic ugly string:
J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM
J0000010: Project name: E:\foo.pf
J0000011: Job name: MBiek Direct Mail Test
J0000020: Document 1 - Completed successfully
I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time).
Here's the regex I've been playing with:
Project name:\s+(.*)\s+J[0-9]{7}:
The problem is that it doesn't stop until it hits the J0000020: at the end.
How do I make the regex stop at the first occurrence of J[0-9]{7}?
Make .* non-greedy by adding '?' after it:
Project name:\s+(.*?)\s+J[0-9]{7}:
Using non-greedy quantifiers here is probably the best solution, also because it is more efficient than the greedy alternative: Greedy matches generally go as far as they can (here, until the end of the text!) and then trace back character after character to try and match the part coming afterwards.
However, consider using a negative character class instead:
Project name:\s+(\S*)\s+J[0-9]{7}:
\S means “everything except a whitespace and this is exactly what you want.
Well, ".*" is a greedy selector. You make it non-greedy by using ".*?" When using the latter construct, the regex engine will, at every step it matches text into the "." attempt to match whatever make come after the ".*?". This means that if for instance nothing comes after the ".*?", then it matches nothing.
Here's what I used. s contains your original string. This code is .NET specific, but most flavors of regex will have something similar.
string m = Regex.Match(s, #"Project name: (?<name>.*?) J\d+").Groups["name"].Value;
I would also recommend you experiment with regular expressions using "Expresso" - it's a utility a great (and free) utility for regex editing and testing.
One of its upsides is that its UI exposes a lot of regex functionality that people unexprienced with regex might not be familiar with, in a way that it would be easy for them to learn these new concepts.
For example, when building your regex using the UI, and choosing "*", you have the ability to check the checkbox "As few as possible" and see the resulting regex, as well as test its behavior, even if you were unfamiliar with non-greedy expressions before.
Available for download at their site:
http://www.ultrapico.com/Expresso.htm
Express download:
http://www.ultrapico.com/ExpressoDownload.htm
(Project name:\s+[A-Z]:(?:\\w+)+.[a-zA-Z]+\s+J[0-9]{7})(?=:)
This will work for you.
Adding (?:\\w+)+.[a-zA-Z]+ will be more restrictive instead of .*
This question already has answers here:
Regular expression to stop at first match
(9 answers)
Closed 2 years ago.
I have this gigantic ugly string:
J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM
J0000010: Project name: E:\foo.pf
J0000011: Job name: MBiek Direct Mail Test
J0000020: Document 1 - Completed successfully
I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time).
Here's the regex I've been playing with:
Project name:\s+(.*)\s+J[0-9]{7}:
The problem is that it doesn't stop until it hits the J0000020: at the end.
How do I make the regex stop at the first occurrence of J[0-9]{7}?
Make .* non-greedy by adding '?' after it:
Project name:\s+(.*?)\s+J[0-9]{7}:
Using non-greedy quantifiers here is probably the best solution, also because it is more efficient than the greedy alternative: Greedy matches generally go as far as they can (here, until the end of the text!) and then trace back character after character to try and match the part coming afterwards.
However, consider using a negative character class instead:
Project name:\s+(\S*)\s+J[0-9]{7}:
\S means “everything except a whitespace and this is exactly what you want.
Well, ".*" is a greedy selector. You make it non-greedy by using ".*?" When using the latter construct, the regex engine will, at every step it matches text into the "." attempt to match whatever make come after the ".*?". This means that if for instance nothing comes after the ".*?", then it matches nothing.
Here's what I used. s contains your original string. This code is .NET specific, but most flavors of regex will have something similar.
string m = Regex.Match(s, #"Project name: (?<name>.*?) J\d+").Groups["name"].Value;
I would also recommend you experiment with regular expressions using "Expresso" - it's a utility a great (and free) utility for regex editing and testing.
One of its upsides is that its UI exposes a lot of regex functionality that people unexprienced with regex might not be familiar with, in a way that it would be easy for them to learn these new concepts.
For example, when building your regex using the UI, and choosing "*", you have the ability to check the checkbox "As few as possible" and see the resulting regex, as well as test its behavior, even if you were unfamiliar with non-greedy expressions before.
Available for download at their site:
http://www.ultrapico.com/Expresso.htm
Express download:
http://www.ultrapico.com/ExpressoDownload.htm
(Project name:\s+[A-Z]:(?:\\w+)+.[a-zA-Z]+\s+J[0-9]{7})(?=:)
This will work for you.
Adding (?:\\w+)+.[a-zA-Z]+ will be more restrictive instead of .*
This question already has answers here:
Regular expression to stop at first match
(9 answers)
Closed 2 years ago.
I have this gigantic ugly string:
J0000000: Transaction A0001401 started on 8/22/2008 9:49:29 AM
J0000010: Project name: E:\foo.pf
J0000011: Job name: MBiek Direct Mail Test
J0000020: Document 1 - Completed successfully
I'm trying to extract pieces from it using regex. In this case, I want to grab everything after Project Name up to the part where it says J0000011: (the 11 is going to be a different number every time).
Here's the regex I've been playing with:
Project name:\s+(.*)\s+J[0-9]{7}:
The problem is that it doesn't stop until it hits the J0000020: at the end.
How do I make the regex stop at the first occurrence of J[0-9]{7}?
Make .* non-greedy by adding '?' after it:
Project name:\s+(.*?)\s+J[0-9]{7}:
Using non-greedy quantifiers here is probably the best solution, also because it is more efficient than the greedy alternative: Greedy matches generally go as far as they can (here, until the end of the text!) and then trace back character after character to try and match the part coming afterwards.
However, consider using a negative character class instead:
Project name:\s+(\S*)\s+J[0-9]{7}:
\S means “everything except a whitespace and this is exactly what you want.
Well, ".*" is a greedy selector. You make it non-greedy by using ".*?" When using the latter construct, the regex engine will, at every step it matches text into the "." attempt to match whatever make come after the ".*?". This means that if for instance nothing comes after the ".*?", then it matches nothing.
Here's what I used. s contains your original string. This code is .NET specific, but most flavors of regex will have something similar.
string m = Regex.Match(s, #"Project name: (?<name>.*?) J\d+").Groups["name"].Value;
I would also recommend you experiment with regular expressions using "Expresso" - it's a utility a great (and free) utility for regex editing and testing.
One of its upsides is that its UI exposes a lot of regex functionality that people unexprienced with regex might not be familiar with, in a way that it would be easy for them to learn these new concepts.
For example, when building your regex using the UI, and choosing "*", you have the ability to check the checkbox "As few as possible" and see the resulting regex, as well as test its behavior, even if you were unfamiliar with non-greedy expressions before.
Available for download at their site:
http://www.ultrapico.com/Expresso.htm
Express download:
http://www.ultrapico.com/ExpressoDownload.htm
(Project name:\s+[A-Z]:(?:\\w+)+.[a-zA-Z]+\s+J[0-9]{7})(?=:)
This will work for you.
Adding (?:\\w+)+.[a-zA-Z]+ will be more restrictive instead of .*
I have a RegEx problem. Consider the following URL:
http://ab.cdefgh.com/aa-BB/index.aspx
I need a regular expression that looks at "aa-BB" and, if it doesn't
match a number of specific values, say:
rr-GG
vv-VV
yy-YY
zz-ZZ
then the URL should redirect to some place. For example:
http://ab.cdefgh.com/notfound.aspx
In web.config I have urlrewrite rules. I need to know what
the regex would be between the tags.
<urlrewrites>
<rule>
<url>?</url>
<rewrite>http://ab.cdefgh.com/notfound.aspx</rewrite>
</rule>
</urlrewrites>
Assuming you don't care about the potential for the replacement pattern to be in the domain name or some other level of the directory structure, this should select on the pattern you're interested in:
http:\/\/ab\.cdefgh\.com\/(?:aa\-BB|rr\-GG|vv\-VV|yy\-YY|zz\-ZZ)\/index\.aspx
where the aa-BB, etc. patterns are simply "or"ed together using the | operator.
To further break this apart, all of the /, ., and - characters need to be escaped with a \ to prevent the regex from interpreting them as syntax. The (?: notation means to group the things being "or"ed without storing it in a backreference variable (this makes it more efficient if you don't care about retaining the value selected).
Here is a link to a demonstration (maybe this can help you play around with the regex here to get to exactly which character combinations you want)
http://rubular.com/r/UfB65UyYrj
Will this help?
^([a-z])\1-([A-Z])\2.*
It matches:
uu-FF/
aa-BB/
bb-CC/index
But not
aaBB
asdf
ba-BB
aA-BB
(Edit based on comment)
Just pipe delimit your desired urls inside of () and escaping special chars.
Eg.
^(xx-YY|yy-ZZ|aa-BB|goodStuff)/.*
But, I think you might actually want the following which matches anything other than the urls that you specify, so that all else goes to notfound.aspx:
^[^(xx-YY|yy-ZZ|aa-BB|goodStuff)]/.*
Assuming you want anything but xx-XX, yy-YY and zz-ZZ to redirect:
[^(xx\-XX)|(yy\-YY)|(zz\-ZZ)]