Rails - Feb 2010 - best way to select uncommon elements from array

I have two arrays and i want to get all items which are NOT common to
both, so basically if i have two arrays A and B, i want all elements
in A that are not in B. what is the best way to do this apart from
using two nested loops.

thanks
rahtha

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On Feb 16, 7:10 am, rahtha
<rahul.that...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
> I have two arrays and i want to get all items which are NOT common to
> both, so basically if i have two arrays A and B, i want all elements
> in A that are not in B. what is the best way to do this apart from
> using two nested loops.
>
A - B ?

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On Tue, Feb 16, 2010 at 8:10 AM, rahtha
<rahul.thathoo-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> I have two arrays and i want to get all items which are NOT common to
> both, so basically if i have two arrays A and B, i want all elements
> in A that are not in B. what is the best way to do this apart from
> using two nested loops.
But do you want the ones in B that are not in A as well? (symmetric difference)

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Nope don''t care about that case just the ones in A that are not in B

On Feb 16, 8:02 am, Xavier Noria
<f...-xlncskNFVEJBDgjK7y7TUQ@public.gmane.org>
wrote:
> On Tue, Feb 16, 2010 at 8:10 AM, rahtha
<rahul.that...-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > I have two arrays and i want to get all items which are NOT common to
> > both, so basically if i have two arrays A and B, i want all elements
> > in A that are not in B. what is the best way to do this apart from
> > using two nested loops.
>
> But do you want the ones in B that are not in A as well? (symmetric
difference)
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rahtha wrote:
> Nope don''t care about that case just the ones in A that are not in
B
Well, then it''s what Frederick said.


irb(main):065:0> a = [1,2,3]
=> [1, 2, 3]
irb(main):066:0> b = [2,4,6]
=> [2, 4, 6]
irb(main):067:0> a-b
=> [1, 3]
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