Sort hash by key, return hash in Ruby

Question

Would this be the best way to sort a hash and return Hash object (instead of Array):

h = {\"a\"=>1, \"c\"=>3, \"b\"=>2, \"d\"=>4}
# => {\"a\"=         


        

Answer 1

Note: Ruby >= 1.9.2 has an order-preserving hash: the order keys are inserted will be the order they are enumerated. The below applies to older versions or to backward-compatible code.

There is no concept of a sorted hash. So no, what you're doing isn't right.

If you want it sorted for display, return a string:

"{" + h.sort.map{|k,v| "#{k.inspect}=>#{v.inspect}"}.join(", ") + "}"

or, if you want the keys in order:

h.keys.sort

or, if you want to access the elements in order:

h.sort.map do |key,value|
  # keys will arrive in order to this block, with their associated value.
end

but in summary, it makes no sense to talk about a sorted hash. From the docs, "The order in which you traverse a hash by either key or value may seem arbitrary, and will generally not be in the insertion order." So inserting keys in a specific order into the hash won't help.