Re: Pair of items

To compare any two groups, you'd do something like:

sub is_ok
{
    my ($x, $y) = @_;
    my (%x, %y);

    @x{@$x} = 1;
    @y{@$y} = 1;

    foreach my $k (keys %x)
    {
        return 0 if exists $y{$k};
    }

    return 1;
}
[download]

Put in a loop, as necessary. Lather, rinse, repeat. A few notes:

This will work with groups of arbitrary size and will also work with groups of different sizes.
It will also work with groups that contain arbitrary data.
It will throw warnings if any of the elements are undef.
It does string comparisons, so 2, 4, 6 and 1.0, 2.0, 3.0 may or may not be ok. I will leave numeric comparisons as an exercise for the reader.

------
We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.

Comment on Re: Pair of items Download Code

Replies are listed 'Best First'.
Re: Pair of items by tadman (Prior) on Jul 29, 2003 at 20:14 UTC
Tweakism to get something like this: `sub is_ok { my ($x, $y) = @_; my %x; @x{@$x} = 1; return !grep { exists($x{$_}) } @$y; }` [download] You seem to create a hash and then just iterate over its keys, instead of just using the straight list. Here I just make one hash and use the other list raw. `grep` is used to produce a list of matches, which is then negated, so that it returns a true value if there are no matches.	[reply] [d/l]
Re: Re: Pair of items by Anonymous Monk on Jul 30, 2003 at 16:09 UTC
Quantum::Superpositions offers an elegant solution: `use Quantum::Superpositions; my $list1 = [1,2,3]; my $list2 = [4,5,6]; print "No common items" if all(@$list1) != all(@$list2);` [download] Basically, if all of the elements in list1 are not equal to all of the elements in list2, that will print "No Common Items" HTH -Tom	[reply] [d/l]
Re3: Pair of items by dragonchild (Archbishop) on Jul 30, 2003 at 16:27 UTC
And, that is the solution I would propose in Perl6. However, Quantum::Superpositions is not a core module nor is it meant to be used in production code. It's a plaything conceived in the bowels of TheDamian's mind that hasn't been thoroughly tested. shrugs TMTOWDI ------ We are the carpenters and bricklayers of the Information Age. The idea is a little like C++ templates, except not quite so brain-meltingly complicated. -- TheDamian, Exegesis 6 Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.	[reply]


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