in reply to Building list::comapre objects for unknown numbers of objects

As the documentation shows, you need to pass listrefs, not a string.

use strict;
use warnings;

use List::Compare;

my @S1 = ( 'G1', 'G3', 'G5' );
my @S2 = ( 'G1', 'G3', 'G5', 'G7', 'G12' );
my @S3 = ( 'G1', 'G5' );

my @A = (\@S1, \@S2, \@S3);

my $lc = List::Compare->new('--unsorted', @A);

my @intersection = $lc->get_intersection;

print "intesection is @intersection\n";

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Re^2: Building List::Compare objects for unknown numbers of objects
by biologistatsea (Acolyte) on Nov 21, 2018 at 12:08 UTC
    Great - thanks for your help. I read the documentation quite carefully and was aware that you need to pass array references. But to someone of my background (biologist with a little self-taught Perl) it wasn't obvious to me that the '->new' method would interpret the @A to provide the array references to generate the object. I suppose I thought it would need something to tell it to look at the contents of @A instead of @A itself. Instead I thought that perl would interpolate the "$var1" first and then the resulting text would be correctly interpreted by the method. I obviously lack some basic understanding here...
[reply]
      I suppose I thought it would need something to tell it to look at the contents of @A instead of @A itself.

      Quite the reverse. You have to work at it in order to refer to the array rather than its contents. Consider these two separate lines from the code above:

      print "intesection is @intersection\n";

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      Here, despite being contained within a string, it is the contents of the array which are printed, not the array as a container.

      my @A = (\@S1, \@S2, \@S3);

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      Whereas here, we have had to create references to each of the S arrays so that they are not flattened when assigning to @A.

      Further reading: Arrays: A Tutorial/Reference, perldata, perlref

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