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RegExp that is giving me fits

tanker
Novice

Mar 22, 2017, 11:04 AM

Post #1 of 5 (15925 views)

RegExp that is giving me fits	Can't Post

I have spent the past couple days trying to get an expression to work and I am definitely missing something. I'm a mid level Perl user.

Source line examples:

Code

<I32>SLEEVE (USE WITH INDEX 2) 
<I31>SPACER, SLEEVE (UNDER BOLT HEAD) (USE WITH INDEX 73)

What I expect to get:

Code

(USE WITH INDEX 2) 
(UNDER BOLT HEAD) (USE WITH INDEX 73)

What I'm getting:

Code

(USE WITH INDEX 2) 
(USE WITH INDEX 73)

My current attempt is the following.

Code

$XYZ =~ s/^(.*)\((.*)\)$/\($2\)/;

I'm trying to capture the notes between the first "(" and the last ")". For some reason I can't get it to keep the first "(...)" in this case. In my current attempt I try to match the beginning of the line followed by any characters up to ( then match any text up to a ) at the end of the string. Then output the contents of the 2nd wildcard between ( ). The way I have written it, I'm thinking (obviously incorrectly) it should even catch (...) (...) (...)

I know it's going to probably be something simple but putting it aside to think about other things, hoping it comes to me, isn't working.

Thanks in advance, Stan

FishMonger
Veteran / Moderator

Mar 22, 2017, 11:26 AM

Post #2 of 5 (15923 views)

Re: [tanker] RegExp that is giving me fits [In reply to]	Can't Post

Code

use 5.010; 
use warnings; 
use strict; 
 
my @lines = ('<I32>SLEEVE (USE WITH INDEX 2)', 
             '<I31>SPACER, SLEEVE (UNDER BOLT HEAD) (USE WITH INDEX 73)'); 
 
foreach my $line (@lines) { 
    say $1 if $line =~ /(\(.+\))/ 
}

(This post was edited by FishMonger on Mar 22, 2017, 11:27 AM)

FishMonger
Veteran / Moderator

Mar 22, 2017, 11:32 AM

Post #3 of 5 (15920 views)

Re: [tanker] RegExp that is giving me fits [In reply to]	Can't Post

If you want to use/fix your substitution regex, the easiest adjustment would be to make the first group to be non-greedy.

Code

s/^(.*?)\((.*)\)$/\($2\)/;

BillKSmith
Veteran

Mar 23, 2017, 7:39 PM

Post #4 of 5 (15902 views)

Re: [tanker] RegExp that is giving me fits [In reply to]	Can't Post

Do you want to match everything from the first open parentheses to the last close parenthesis? Try this

Code

use strict; 
use warnings; 
 
my @lines = ( 
    '<I32>SLEEVE (USE WITH INDEX 2)', 
    '<I31>SPACER, SLEEVE (UNDER BOLT HEAD) (USE WITH INDEX 73)' 
); 
foreach my $line (@lines) { 
    $line =~ s/.*?(\(.*)\)/$1/; 
    print $line, "\n"; 
} 
 
OUTPUT: 
(USE WITH INDEX 2)  
(UNDER BOLT HEAD) (USE WITH INDEX 73)

Good Luck,
Bill

tanker
Novice

Mar 24, 2017, 6:30 AM

Post #5 of 5 (15891 views)

Re: RegExp that is giving me fits [In reply to]	Can't Post

Thanks for the reply to you both. Sorry I didn't reply earlier, been one of those weeks. Boss man, needed something urgently (ain't that always the case Smile

) and had to put everything else on hold.

I guess I should have mentioned but didn't know how much to include in my question. The substitution was already within a while loop that reads the line from a file.

FishMonger your second reply is exactly what I was looking for. Thank you. The only change I made after testing it was to replace the "$" at the end of the match string with a "\n" so that it removes the new line.

Thanks again guys,
Stan

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