delete array elements by certain criteria

Question

What's the best and way to do this: I have two arrays:

a=[['a','one'],['b','two'],['c','three'],['d','four']]

and b=['two','three']

I want to delete nested arrays inside a that include elements in b,to get this:

[['a','one']['d','four']

Thanks.

Answer 1

a = [['a','one'],['b','two'],['c','three'],['d','four']]
b = ['two','three']

a.delete_if { |x| b.include?(x.last) }

p a
# => [["a", "one"], ["d", "four"]]

Answer 2

rassoc to the rescue!

 b.each {|el| a.delete(a.rassoc(el)) }