Ruby’s Hash Vs ActiveSupport’s HashWithIndifferentAccess

The Hash class in Ruby’s core library retrieves values by doing a standard == comparison on the keys. This means that a value stored for a Symbol key (e.g. :some_value) cannot be retrieved using the equivalent String (e.g. ‘some_value’). 

On the other hand, class HashWithIndifferentAccess is inherited from ruby "Hash" & a special behavior is added in it. HashWithIndifferentAccess treats Symbol keys and String keys as equivalent so that the following would work:

h = HashWithIndifferentAccess.new
h[:my_value] = 'foo'
h['my_value'] #=> will return "foo"