It's often useful to see what's actually in a structure like an array or hash:

c:\@Work\Perl\monks>perl -wMstrict -le
"use Data::Dump qw(pp);
 ;;
 my @foo;
 my $bar;
 ;;
 $bar = 42;               push @foo, $bar;  print 'A: ', pp(@foo);
 $bar = 'abc' =~ /abc/;   push @foo, $bar;  print 'B: ', pp(@foo);
 $bar = 'abc' =~ /abcd/;  push @foo, $bar;  print 'C: ', pp(@foo);
 $bar = '';               push @foo, $bar;  print 'D: ', pp(@foo);
 $bar = 0;                push @foo, $bar;  print 'E: ', pp(@foo);
 $bar = undef;            push @foo, $bar;  print 'F: ', pp(@foo);
                          push @foo, ();    print 'G: ', pp(@foo);
"
A: 42
B: (42, 1)
C: (42, 1, "")
D: (42, 1, "", "")
E: (42, 1, "", "", 0)
F: (42, 1, "", "", 0, undef)
G: (42, 1, "", "", 0, undef)
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See Data::Dump, which is not core, or Data::Dumper, which is.