is it possible to define a regex pattern which checks eg. for 3 terms independent to their position in the main string?
eg. my string is something like "click here to unsubscribe: http://www.url.com"
the pattern should also work with "http:// unsubscribe click"
thx
You can use positive lookaheads. For example,
(?=.*click)(?=.*unsubscribe).*http
is a regex that will look ahead from the current position (without moving ahead) for click, then for unsubscribe, then search normally for http.
It's possible, but results in very complicated regexs, e.g.:
/(click.*unsubscribe|unsubscribe.*click)/
Basically, you would need to have a different regex section for each order. Not ideal. Better to just use multiple regexes, one for each term.
Yes, using conditionals.
http://www.regular-expressions.info/conditional.html
Related
I have multiple elements popup, email and webhook.
They can come in a string formated like :
popup|email|webhook
email|webhook
webhook
email
email|webhook
popup|webhook
popup|email
popup
I actually got a regex ^(?:popup){0,1}?\|?(?:email){0,1}?\|?(?:webhook){0,1}?$ but it will match popup|email|webhook as well as popupemail|webhook.
Is there a way to ensure elements are separated with my separatator | ?
I also had (?>(?>(?>popup\|?){0,1}?email\|?){0,1}?webhook){0,1}? but this is not a solution obvisously as it will work in one direction only, I'm nearly sure this is easily solvable but I dont know in wich way to look in the Regex world.
You just need to add word boundaries to make sure that two words are never together.
^(?:popup)?\b\|?\b(?:email)?\b\|?\b(?:webhook)?$
Demo
Given an XML document, I'd like to be able to pick out individual key/value pairsfrom a particular tag:
<aaa>key0:val0 key1:val1 key2:va2</aaa>
I'd like to get back
key0:val0
key1:val1
key2:val2
So far I have
(?<=<aaa>).*(?=<\/aaa>)
Which will match everything inside, but as one result.
I also have
[^\s][\w]*:[\w]*[^\s] which will also match correctly in groups on this:
key0:val0 key1:val1 key2:va2
But not with the tags. I believe this is an issue with searching for subgroups and I'm not sure how to get around it.
Thanks!
You cannot combine the two expressions in the way you want, because you have to match each occurrence of "key:value".
So in what you came up with - (?<=<abc>)([\w]*:[\w]*[\s]*)+(?=<\/abc>) - there are two matching groups. The bigger one matches everything inside the tags, while the other matches a single "key:value" occurrence. The regex engine cannot give each individual occurence because it does not work that way. So it just gives you the last one.
If you think in python, on the matcher object obtained after applying you regex, you will have access to matcher.group(1) and matcher.group(2), because you have two matching ( ) groups in the regex.
But what you want is the n occurences of "key:value". So it's easier to just run the simpler \w+:\w+ regex on the string inside the tags.
I uploaded this one at parsemarket, and I'm not sure its what you are looking for, but maybe something like this:
(<aaa>)((\w+:\w+\s)*(\w+:\w+)*)(<\/aaa>)
AFAIK, unless you know how many k:v pairs are in the tags, you can't capture all of them in one regex. So, if there are only three, you could do something like this:
<(?:aaa)>(\w+:\w+\s*)+(\w+:\w+\s*)+(\w+:\w+\s*)+<(?:\/aaa)>
But I would think you would want to do some sort of loop with whatever language you are using. Or, as some of the comments suggest, use the parser classes in the language. I've used BeautifulSoup in Python for HTML.
Hi I have a Stylesheet where i use xsl:analyze-string with the following regex:
(&journal_abbrevs;)[\s ]*([0-9]{{4}})[,][\s ][S]?[\.]?[\s ]?([0-9]{{1,4}})([\s ][(][0-9]{{1,4}}[)])?
You don't need to look at the whole thing :)
&journal_abbrevs; looks like this:
"example-String1|example-String2|example-String3|..."
What I need to do know is exclude one of the strings in &journal_abbrevs; from this regex. E.g. I don't want example-String1 to be matched.
Any ideas on how to do that ?
It seems XSLT regex does not support look-around. So I don't think you'll be able to get a solution for this that does not involve writing out all strings from journal_abbrevs in your regex. Related question.
To minimize the amount of writing out, you could split journal_abbrevs into say journal_abbrevs1, journal_abbrevs2 and journal_abbrevs3 (or how many you decide to use) and only write out whichever one that contains the string you wish to exclude. If journal_abbrevs1 contains the string, you'd then end up with something like:
((&journal_abbrevs2;)|(&journal_abbrevs3;)|example-String2|example-String3|...)...
If it supported look-around, you could've used a very simple:
(?!example-String1)(&journal_abbrevs;)...
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/
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.