Re: Need to Create an Array of Differences

Here's the hash way,

# given @a, @b
my @c = do {
    my %a;
    @a{@a} = ();   # slice of %a, values undef
    delete @a{@b}; # delete the @b slice
    keys %a;
};
[download]

That may not be exactly what you want. If @a contains duplicate elements you wish to keep, this will not duplicate them in @c. If the order of @a is important, this will not preserve it in @c.

In those cases I would write code much like yours or Aristotle's or revdiablo's.

After Compline,
Zaxo

Comment on Re: Need to Create an Array of Differences Download Code

Replies are listed 'Best First'.
Re^2: Need to Create an Array of Differences by scottj (Monk) on Aug 03, 2004 at 02:13 UTC
I ended up doing something like this: `# given @a, @b my %a; @a{@a} = (); delete @a{@b}; my @c = keys %a;` [download] This code works just as well as my previous code with the exception that the new code is much faster. Thanks! -Scott	[reply] [d/l]
Re^3: Need to Create an Array of Differences by revdiablo (Prior) on Aug 03, 2004 at 04:02 UTC
I assume the code does what you need, but there are a few caveats that should be mentioned. This code will change the order of the values, and it will eliminate any duplicates. This may or may not be a problem, depending on what it's being used for. Update: these caveats were noted, in Zaxo's original node, I just failed to notice. My apologies.	[reply]