Implements a much needed Hash#zip method.

To install run gem install hash-zip, and then require "hash-zip" in your code.

You can zip multiple Hashes. Keys in result will be keys in any of the inputs, and values will be Arrays with missing values padded by nils.

a = {x: 1, y: 2}
b = {y: 3, z: 4}
a.zip(b)
# returns {x: [1, nil], y: [2, 3], z: [nil, 4]}

You can also use it with a block. In such case the return value is nil:

a = {x: 1, y: 2}
b = {y: 3, z: 4}
a.zip(b) do |key, value_a, value_b|
  p [key, value_a, value_b]
  # Yields [:x, 1, nil]
  #        [:y, 2, 3]
  #        [:z, nil, 4]
end

It works with more than one argument (a.zip(b,c)) as well as with zero arguments (a.zip()).

You can also use the zip_compact variant which discards nil values:

a = {x: 1, y: 2}
b = {y: 3, z: 4}
a.zip_compact(b) do |key, value_a, value_b|
  p [key, value_a, value_b]
  # Yields [:x, 1]
  #        [:y, 2, 3]
  #        [:z, 4]
end

If arguments are not Hashes, but accept to_h, they will be converted automatically before zipping.