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Regex Last variable in string (Identify all characters following the final space in a string - unless last characters is single)

I am trying to gather all of the characters following the final space in a string but am struggling with the syntax. Can anyone help please? The last set of characters will always be alphanumeric but will be of differing characters and amount of characters.

In the below example I would only want to highlight cat.

dog xxx-klsfkd-sdf-sdf cat

And in the next one aaaaaaaaaaaaaddddddddddddddd

heht ooijl-nanhjhsh aaaaaaaaaaaaaddddddddddddddd

however if the final character in the string is single I wish to ignore it e.g.

heht ooijl-nanhjhsh aaaaaaaaaaaaaddddddddddddddd 0

would still highlight aaaaaaaaaaaaaddddddddddddddd

Many Thanks

Bill Prew

I think one approach would be the following, and then get the first submatch. This should discard any cases of a trailing space followed by a single character.

([a-zA-Z0-9]{2,})( [a-zA-Z0-9]){0,1}$

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»bp

Bill Prew

What about this case, what would you want here?

heht ooijl-nanhjhsh aaaaaaaaaaaaaddddddddddddddd 0 1 2 3

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jay_waugh

ASKER

Hi Bill,

What you have suggested isn't currently in play, but if it was it would still be the

aaaaaaaaaaaaaddddddddddddddd

Thanks

Bill Prew

Okay, if it were I think this would handle that as well.

([a-zA-Z0-9]{2,})( [a-zA-Z0-9]){0,}$

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jay_waugh

ASKER

Thanks Bill but sadly that doesn't seem to work as I'd hoped.

I also failed to mentioned that some of the strings that I wish to highlight can contain underscores if that makes any difference.

for example when I use that code on the below FRANK 0 is highlighted

NewYork abcdefg fghkmj-asdasd-efeefe-efeffe FRANK 0

equally for

NewYork abcdefg fghkmj-asdasd-efeefe-efeffe FRANK_Dave 0

Dave 0 is highlighted

Bill Prew

What language or environment are you working in, REGEX varies a bit by context.

And are you taking the first submatch from the results, not the full results?

»bp

Bill Prew

Take a look at the test cases here, it seems to work if you take just subgroup 1 of the match results...

https://regex101.com/r/qlAarF/6

(\S{2,})( \S){0,}$

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jay_waugh

ASKER

OK thanks, I have been using http://pythex.org/ to check the regex and it is giving different results.

I'll try in the application instead and get back to you.

Bill Prew

Seems to yield the same results, just remember you don't want the whole match, just the first group.

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jay_waugh

ASKER

ok thanks, but how do I only return match group 1 and ignore group 2. Again just using the single line of code?

Bill Prew

What language are you working in, and what would the single line of code look like?

»bp

Bill Prew

If python, then this is the idea.

import re
m = re.search('(\S{2,})( \S){0,}$', 'NewYork abcdefg fghkmj-asdasd-efeefe-efeffe FRANK_Dave 0')
print m.group(1)

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jay_waugh

ASKER

Sadly I have to use the Regular expression in an application which doesn't give me the option to use the Python code that you have suggested. I can only type "(\S{2,})( \S){0,}$"

Bill Prew

Okay, as long as the application supports lookaround in the regex patterns then I think this should work.

\S{2,}(?=( \S{1})*$)

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https://regex101.com/r/qlAarF/7

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jay_waugh

ASKER

:( curses it doesn't seem to as expected. In this instance I get two values returned one blank and one with the correct string.

Many thanks for your continued engagement, do you have any more ideas?

Bill Prew

Not unless the application calls out the "flavor" of regex engine it uses. Lookaround is pretty common these days but not ubiquitous.

In the application, you use the regex for extracting data from a field, not just validating, right?

Regex can be a pretty deep dive with additional complex features. I'm not aware of another way to skin this cat, but that doesn't guarantee that there isn't one. Doesn't feel probable, but there is a chance I suppose.

There is a solid "tutorial" on some of the more advanced regex features at the link below, if you are feel courageous...

http://www.regular-expressions.info/tutorial.html

»bp

jay_waugh

ASKER

:) I've bought a book too!!!

So that I can finish what I'm doing though can you please just confirm what I'd need to do the selection of the string but ignoring the single character at the end?

e.g.
NewYork abcdefg fghkmj-asdasd-efeefe-efeffe FRANK_Dave 0

highlights

FRANK_Dave

The same code would also need to work for

heht ooijl-nanhjhsh aaaaaaaaaaaaaddddddddddddddd 0

And just highlight

aaaaaaaaaaaaaddddddddddddddd

etc etc

Can I do that without using multiple subgroups?

Thanks again

ASKER CERTIFIED SOLUTION

Bill Prew

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