Splitting on a pattern once

perlpal has asked for the wisdom of the Perl Monks concerning the following question:

Hi Perl Monks,

I need to split a string which has multiple repitititions of a pattern only on the first occurrence of the pattern.

Case in point being the string mentioned below :

          Aggregate:    f3050-184-160:EmptyAggr
[download]

I need to split the string on ":" on the first occurrence only i.e when it appears after Aggregate.

Is this possible via split in a single step or do i need to post-process the array after split.

Thanks in advance!

Comment on Splitting on a pattern once Download Code

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Re: Splitting on a pattern once by almut (Canon) on Mar 03, 2010 at 18:19 UTC
You can specify the number pieces you want: `#!/usr/bin/perl -l my $s = "Aggregate: f3050-184-160:EmptyAggr"; my ($first, $rest) = split /:/, $s, 2; # ^ print "\$first: '$first'"; print "\$rest: '$rest'"; __END__ $first: 'Aggregate' $rest: ' f3050-184-160:EmptyAggr'` [download]	[reply] [d/l]
Re: Splitting on a pattern once by ikegami (Patriarch) on Mar 03, 2010 at 18:20 UTC
Check out `split`'s 3rd arg. `my ($k,$v) = split(/:/, $_, 2);` [download]	[reply] [d/l] [select]
Re^2: Splitting on a pattern once by ungalnanban (Pilgrim) on Mar 05, 2010 at 10:49 UTC
Is there any way to split the string from last occurrence.? I tried with positive values and negative value in 3rd argument of split(). --sugumar--	[reply]
Re^3: Splitting on a pattern once by kiruthika.bkite (Scribe) on Mar 18, 2010 at 10:47 UTC
Is this you are expecting. Example-1 `my $str="1 2 3 4 590"; my ($a,$b)=split(/ ([^ ]+)$/, $str); print "a=$a\nb=$b\n";` [download] Output a=1 2 3 4 b=590 Example-2 `my $str="1:2:3:4:590"; my ($a,$b)=split(/:([^:]+)$/, $str); print "a=$a\nb=$b\n";` [download] Output a=1:2:3:4 b=590	[reply] [d/l] [select]
Re^3: Splitting on a pattern once by kiruthika.bkite (Scribe) on Mar 22, 2010 at 10:58 UTC
Use the following way to achieve your requirement. `my $str="1:2:3"; my $name=(split(':',$str))[-1];` [download] -1 will return the value of last index.	[reply] [d/l]
Re^3: Splitting on a pattern once by ikegami (Patriarch) on Mar 05, 2010 at 17:31 UTC
You could play with `reverse`, but this is simpler: `my ($k,$v) = /^(.:)?(.)/s;` [download]	[reply] [d/l] [select]
Re^3: Splitting on a pattern once by Anonymous Monk on Mar 18, 2010 at 11:04 UTC
You should read the documentation for split as a negative limit has special meaning.	[reply]
Re: Splitting on a pattern once by toolic (Bishop) on Mar 03, 2010 at 18:24 UTC
If you want to just split on the 1st :, use split with a LIMIT of 2: `use strict; use warnings; my $s = ' Aggregate: f3050-184-160:EmptyAggr'; my ($first, $rest) = split /:/, $s, 2; print "$first\n"; print "$rest\n"; __END__ Aggregate f3050-184-160:EmptyAggr` [download]	[reply] [d/l]
Re: Splitting on a pattern once by ikegami (Patriarch) on Mar 18, 2010 at 15:05 UTC
Alternative: `my ($name, $val) = split /:\s*/; my @val = split /:/, $val;` [download] Then just check `$vals[1]`. The advantage is that you can also check if you're looking at the right field (by checking `$name`	[reply] [d/l] [select]


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