pairwise() doesn't seem to work...

7stud has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,

This is what I get when I try to use pairwise() in List::MoreUtils,

 
use strict;
use warnings;
use 5.010;

use List::MoreUtils;

my @arr1 = (1, 2, 3);
my @arr2 = (10, 20, 30);

my %hash = pairwise { ($a, $b) } @arr1, @arr2;

use Data::Dumper;
say Dumper(\%hash);



--output:--
Name "main::b" used only once: possible typo at 1perl.pl line 10.
Name "main::a" used only once: possible typo at 1perl.pl line 10.
Can't call method "pairwise" on an undefined value at 1perl.pl line 10
+.
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Comment on pairwise() doesn't seem to work... Download Code

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Re: pairwise() doesn't seem to work... by Corion (Patriarch) on Oct 06, 2010 at 09:19 UTC
You need to import `pairwise` from List::MoreUtils. It seems that Perl interprets `pairwise { ($a, $b) }` as indirect object notation otherwise: `use List::MoreUtils qw( pairwise );` [download]	[reply] [d/l] [select]
Re: pairwise() doesn't seem to work... by eyepopslikeamosquito (Archbishop) on Oct 06, 2010 at 09:20 UTC
You need to explicitly import `pairwise` like so: `use List::MoreUtils qw(pairwise);` [download]	[reply] [d/l] [select]
Re^2: pairwise() doesn't seem to work... by 7stud (Deacon) on Oct 06, 2010 at 09:37 UTC
Thanks.	[reply]
Re: pairwise() doesn't seem to work... by AnomalousMonk (Archbishop) on Oct 06, 2010 at 10:02 UTC
And get rid of the `Name "main::whatever" used only once ...` warnings with a `use vars qw($a $b);` (or similar) statement. `>perl -wMstrict -le "use 5.010; use List::MoreUtils qw(pairwise); my @arr1 = (1, 2, 3); my @arr2 = (10, 20, 30); use vars qw($a $b); my %hash = pairwise { ($a, $b) } @arr1, @arr2; use Data::Dumper; say Dumper(\%hash); " $VAR1 = { '1' => 10, '3' => 30, '2' => 20 };` [download]	[reply] [d/l] [select]