Is there any way to make an array non-greedy?

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

Hi all, I'm trying to split some data that has a series of related values in the middle. Ideally, I'd like to be able to split them right into their eventual home, which will be an array. I've come up with a toy script that hopefully demonstrates what I'd like

use strict;
use warnings;

my $string = join('x', 'a'x20);

my (@foo, $foo);

(@foo[0..18], $foo) = split('x', $string);
print "Success!\n" if $foo eq "a";
[download]

I thought that explicitly supplying the indicies for the array would help, but no dice. Is there some clever way to pull this off?

thor

Feel the white light, the light within Be your own disciple, fan the sparks of will For all of us waiting, your kingdom will come

Update: It looks like I had an error in my test code, as most of you stated below. Just goes to show you that you can't trust yourself sometimes. Thanks for the help!

Comment on Is there any way to make an array non-greedy? Download Code

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Re: Is there any way to make an array non-greedy? by ikegami (Patriarch) on Oct 14, 2005 at 16:56 UTC
You have a bug: `my $string = join('x', 'a'x20);` should be `my $string = join('x', ('a')x20);` Fix that and it works. If you always have one element left over, you can make the code readable as: `use strict; use warnings; my $string = join('x', ('a')x20); my @foo = split('x', $string); my $foo = pop(@foo); print "Success!\n" if $foo eq "a";` [download] If you always have a variable number of elements left over, you have a problem fixed as follows: `use strict; use warnings; my $string = join('x', ('a')x20); my (@foo, $foo); (@foo[0..18], $foo) = split('x', $string, 20); # <-- added limit. print "Success!\n" if $foo eq "a";` [download]	[reply] [d/l] [select]
Re^2: Is there any way to make an array non-greedy? by thor (Priest) on Oct 14, 2005 at 18:25 UTC
If my real problem were as easy as my toy script, I'd certainly follow one of your above solutions. However, it's more like this: `my ( $field1, $field2, #... $field25, @field26[0..25], $field27, $field28, #... ) = split(/\\|/);` [download] This way, it makes it obvious that I'm grabbing a fixed number from the split return. I appreciate the terseness in your solutions, though. Now that I know that it was a problem with my test data and not my approach, I'll be using something like what I originally posted. thor `Feel the white light, the light within Be your own disciple, fan the sparks of will For all of us waiting, your kingdom will come`	[reply] [d/l]
Re^3: Is there any way to make an array non-greedy? by duff (Parson) on Oct 15, 2005 at 03:56 UTC
I think you're after something like this: `@important_fields = (split /\\|/, $string)[25..50];` [download] duff	[reply] [d/l]
Re: Is there any way to make an array non-greedy? by sk (Curate) on Oct 14, 2005 at 16:53 UTC
Did you mean to do this? `use strict; use warnings; my $string = join('x', ('a')x20); ### NOTE the ()'s print $string,$/; my (@foo, $foo); (@foo[0..18], $foo) = split('x', $string); print $foo[0],$/; print "Success!\n" if $foo eq "a"; __END__ axaxaxaxaxaxaxaxaxaxaxaxaxaxaxaxaxaxaxa a Success!` [download] I don't quite understand your `join('x', 'a'x20);` otherwise. Why join a scalar? cheers SK	[reply] [d/l] [select]
Re: Is there any way to make an array non-greedy? by xdg (Monsignor) on Oct 14, 2005 at 17:00 UTC
For this case, where you only want one item, reverse your split: `use strict; use warnings; my $string = join('x', ('a') x 20); my (@foo, $foo); ($foo, @foo) = reverse( split('x', $string) ); print "\$foo:$foo\n"; print "\@foo:@foo\n";` [download] Prints `$foo:a @foo:a a a a a a a a a a a a a a a a a a a` [download] Note the fix in your `$string` line to put 'a' as a list -xdg Code written by xdg and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.	[reply] [d/l] [select]
Re: Is there any way to make an array non-greedy? by nothingmuch (Priest) on Oct 15, 2005 at 03:50 UTC
`my $foo = (split "x", $string)[19];` -nuffin zz zZ Z Z #!perl	[reply] [d/l]
Re: Is there any way to make an array non-greedy? by Anonymous Monk on Oct 14, 2005 at 16:54 UTC
$string only has 1 x	[reply]


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