Question

I’m trying to zip 3 arrays into a hash. The hash is coming up empty, though. Here’s sample code to reproduce using Ruby 1.9:

>> foo0 = ["a","b"]
=> ["a", "b"]
>> foo1 = ["c","d"]
=> ["c", "d"]
>> foo2 = ["e", "f"]
=> ["e", "f"]
>> h = Hash[foo0.zip(foo1, foo2)]
=> {}

I’d like to zip these and then do something like:

h.each_pair do |letter0, letter1, letter2|
   # process letter0, letter1
end

Answer 1

It’s not clear what you expect the output to be but the [] operator of the Hash class is intended to take an even number of arguments and return a new hash where each even numbered argument is the key for the corresponding odd numbered value.

For example, if you introduce foo3 = ["d"] and you want to get a hash like {"a"=>"b", "c"=>"d"} you could do the following:

>> Hash[*foo0.zip(foo1, foo2, foo3).flatten]
=> {"a"=>"b", "c"=>"d"}