When should I use Struct vs. OpenStruct?

Question

In general, what are the advantages and disadvantages of using an OpenStruct as compared to a Struct? What type of general use-cases would fit each of these?

Answer 1

OpenStructs use significantly more memory and are slower performers versus Structs.

require 'ostruct' 

collection = (1..100000).collect do |index|
   OpenStruct.new(:name => "User", :age => 21)
end

On my system the following code executed in 14 seconds and consumed 1.5 GB of memory. Your mileage might vary:

User = Struct.new(:name, :age)

collection = (1..100000).collect do |index|
   User.new("User",21)
end

That finished nearly instantaneously and consumed 26.6 MB of memory.