•Re: finding union, intersection and differences of arrays

my @a = qw(a b c d e f);
my @b = qw(c d e f g h);
my ($only_a, $only_b, $both, $either) = listy(\@a, \@b);
print "only in a: @$only_a\n";
print "only in b: @$only_b\n";
print "both: @$both\n";
print "either: @$either\n";

sub listy {
  my %tmp1;
  for (0..1) {
    for my $k (@{$_[$_]}) {
      $tmp1{$k} .= $_;
    }
  }
  my %tmp2;
  while (my($k, $v) = each %tmp1) {
    push @{$tmp2{$v}}, $k;
  }
  return @tmp2{"0", "1", "01"}, [keys %tmp1]; 
}
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-- Randal L. Schwartz, Perl hacker

Comment on •Re: finding union, intersection and differences of arrays Download Code

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Re: •Re: finding union, intersection and differences of arrays by Jasper (Chaplain) on Mar 28, 2002 at 18:06 UTC
I seem to have nothing better to do, but in case you have more than two arrays.. `my ($only_a, $only_b, $only_c, $all, $any) = listy(\@a, \@b, \@c); sub listy { my %tmp1; my @keys; for (0..$#_) { my $key = pop @keys; push @keys, $_, (defined $key ? $key : '') . $_; for my $k (@{$_[$_]}) { $tmp1{$k} .= $_; } } my %tmp2; while (my($k, $v) = each %tmp1) { push @{$tmp2{$v}}, $k; } return @tmp2{@keys}, [keys %tmp1]; }` [download] (maybe I should have tested it better the first time. Fixed bug) Jasp	[reply] [d/l]

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Re: •Re: finding union, intersection and differences of arrays
by Jasper (Chaplain) on Mar 28, 2002 at 18:06 UTC

my ($only_a, $only_b, $only_c, $all, $any) = listy(\@a, \@b, \@c);

sub listy {
  my %tmp1;
  my @keys;
  for (0..$#_) {
    my $key = pop @keys;
    push @keys, $_, (defined $key ? $key : '') . $_;
    for my $k (@{$_[$_]}) {
      $tmp1{$k} .= $_;
    }
  }
  my %tmp2;
  while (my($k, $v) = each %tmp1) {
    push @{$tmp2{$v}}, $k;
  }
  return @tmp2{@keys}, [keys %tmp1];
}
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[reply]
[d/l]