in reply to Printing and Removing Duplicates in Arrays

Here's one way: 
my @ary1 = (1, 2, 3, 4, 5, 6, 7);
my @ary2 = (6, 7, 8, 9, 10, 11);

my %h1 = map {$_ => 1} @ary1;
my %h2 = map {$_ => 1} @ary2;

my %dupes;
@ary1 = grep {(! (exists $h1{$_} and exists $h2{$_})) or do{$dupes{$_}
+=1;0}} @ary1;
@ary2 = grep {(! (exists $h1{$_} and exists $h2{$_})) or do{$dupes{$_}
+=1;0}} @ary2;

print "ary1 is @ary1 \n";
print "ary2 is @ary2 \n";
my @dupes = keys %dupes;
print "dupes were @dupes \n";

[download]

Hope that helps,
andye.

Edited to make dupes a hash rather than an array, to prevent dupes in the dupes!
Another minor edit to prevent a warning

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Re: Re: Printing and Removing Duplicates in Arrays
by jmcnamara (Monsignor) on Aug 21, 2002 at 11:04 UTC

    That's nice. ++

    However, you don't need to check if an element exists in the current array: 

        my @ary1 = (1, 2, 3, 4, 5, 6, 7);
    my @ary2 = (6, 7, 8, 9, 10, 11);

    my %h1;
    my %h2;
    @h1{@ary1} = undef;
    @h2{@ary2} = undef;

    my @dupes;
    @ary1 = grep {not exists $h2{$_} or not push @dupes, $_} @ary1;
    @ary2 = grep {not exists $h1{$_}                       } @ary2;

    print "ary1 is @ary1 \n";
    print "ary2 is @ary2 \n";
    print "dupes were @dupes \n";

    [download]

    Or even just this: 

        @dupes = grep {    exists $h2{$_}} @ary1;
    @ary1  = grep {not exists $h2{$_}} @ary1;
    @ary2  = grep {not exists $h1{$_}} @ary2;

    [download]

    --
    John.

[reply]
[d/l]
[select]
      duh! (smacks own head) You're right. 
      @ary1 = grep {!exists $h2{$_} or $dupes{$_}=0} @ary1;
@ary2 = grep {!exists $h1{$_}                } @ary2;

      [download]

      andye.

      minor edit

[reply]
[d/l]

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