rails - Finding intersections between multiple arrays
Use the & method of Array which is for set intersection.
For example:
> [1,2,3] & [2,3,4] & [0,2,6]
=> [2]
If you want a simpler way to do this with an array of arrays of unknown length, you can use inject.
> arrays = [code1,code2,code3]
> arrays.inject(:&) # Ruby 1.9 shorthand
=> [2]
> arrays.inject{|codes,x| codes & x } # Full syntax works with 1.8 and 1.9
=> [2]