Regex get last matched occurence from matches

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Hi,

I am trying to write a regex in .NET application to get the country name from a specific string and i am able to make something but it's not completely what i need. I have this type of string line as input:

C0230: R1410: S.05.02.01.04: Home Country - life obligations: Gross: Top 5 countries (by amount of gross premiums written) - non-life obligations: Top 5 countries (by amount of gross premiums written) - life obligations: USA

and i need to get out the country name in there only if the C0230, R1410 and S.05.02 are present in the line, otherwise i will not match the country name or will not use it.

What I have tried:

The following regex is giving three matches back and the last one is which i am interested it, but i am looking for a solution within regex to just only match the last one.

C#

(?<=(?i)((C)0230).*((R)1410).*((S)\.05.02).*(life obligations)).[^\d]*\b

Can somebody please point me to how it can be done?

Posted 10-Jan-18 3:30am

Ehsan Sajjad

Updated 10-Jan-18 10:28am

v2

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3 solutions

Solution 3

Just a few interesting links to help building and debugging RegEx.
Here is a link to RegEx documentation:
perlre - perldoc.perl.org[^]
Here is links to tools to help build RegEx and debug them:
.NET Regex Tester - Regex Storm[^]
Expresso Regular Expression Tool[^]
RegExr: Learn, Build, & Test RegEx[^]
This one show you the RegEx as a nice graph which is really helpful to understand what is doing a RegEx:
Debuggex: Online visual regex tester. JavaScript, Python, and PCRE.[^]

Posted 10-Jan-18 10:27am

Patrice T

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OriginalGriff · Accepted Answer · 2018-01-10T03:48:00

Solution 1

Try this:

(?<=C0230.+?R1410.+S\.05\.02)(.+:){5}(?<Country>.+)$

Then use the "Country" group to get the data you are interested in.

Posted 10-Jan-18 3:48am

OriginalGriff

Comments

Ehsan Sajjad 10-Jan-18 10:00am

the problem is country name can be any

OriginalGriff 10-Jan-18 10:15am

Yes - and it matches any.

Or do you mean it can be anywhere?

Ehsan Sajjad 11-Jan-18 7:44am

never mind, this works for the example posted in question but i was actually looking for something more generic, like your regex is looking for 5 occurrences of : sign and it would not be exactly 5 in every case, can be more or less, but country would be at end.

OriginalGriff 11-Jan-18 7:51am

Then either change the {5} to a simpler "+" or "*" and give it a try, or better, use the regex to identify the rows you need to process, and use LastIndexOf to get the final data. The more complex you make a regex, the harder it is to understand and modify when the data changes - so a "combination" approach can produce a lot better and more reliable code in the long term.

Thomas Daniels · Accepted Answer · 2018-01-10T03:50:00

Solution 2

If you put a dollar sign at the end, it will only return the last match (because $ means "end of the line" in a regular expression).

When I tried this out, it matched ": USA" rather than "USA" and to fix that, you can add .*: (note the space after the colon) to the end of the (?<= ) group, and then you can replace the whole .[^\d]*\b part by \w+ (\w is a "word character").

So, all this together gives:

(?<=(?i)((C)0230).*((R)1410).*((S)\.05.02).*(life obligations).*: )\w+$

(Or, an alternative without regex: check that the string contains C0230 and everything else, then split on ": " and grab the last element of the result array)

Posted 10-Jan-18 3:50am

Thomas Daniels

Comments

Ehsan Sajjad 10-Jan-18 10:02am

i am limited here to only use regex, your suggestion would help i think, do you mean putting $ will is forcing it to just grap the end of line match ?

Thomas Daniels 10-Jan-18 10:04am

$ means "end of the line", so this will match a sequence of "word characters" that's immediately followed by the end of the line.

Ehsan Sajjad 10-Jan-18 10:08am

ok great, so let's say in another example i don't have country name at end, in that case this would fail ?

Thomas Daniels 10-Jan-18 10:09am

Yes, it would fail - I made this regex specifically for strings with the country name at the end, because that was your example.

Ehsan Sajjad 10-Jan-18 10:15am

ok, thanks for suggesting the $ thing again, i think this will keep me going for now and your answer is valid as per my need for now, so accepting it, thanks once again :)

Thomas Daniels 10-Jan-18 10:16am

You're welcome!

Regex get last matched occurence from matches

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Regex get last matched occurence from matches

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