# 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

On Feb 16, 7:10 am, rahtha [email protected] 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 ?

On Tue, Feb 16, 2010 at 8:10 AM, rahtha [email protected] 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)

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

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]