Ruby class types and case statements

ruby duck-typing case-statement
Daisy Sophia Hollman picture Daisy Sophia Hollman · Oct 11, 2010 · Viewed 43.8k times · Source

What is the difference between

case item.class
when MyClass
  # do something here
when Array
  # do something different here
when String
  # do a third thing
end

and 

case item.class
when MyClass.class
  # do something here
when Array.class
  # do something different here
when String.class
  # do a third thing
end

For some reason, the first one of these works sometimes and the second doesn't, and other times, the second one works and the first one doesn't. Why? Which one is the "proper" way to do it?

Answer

Nakilon picture Nakilon · Oct 11, 2010

You must use:

case item
when MyClass
...

I had the same problem: How to catch Errno::ECONNRESET class in "case when"?

Related questions

How do Ruby programmers do type checking?

Since there is no type in ruby, how do Ruby programmers make sure a function receives correct arguments? Right now, I am repeating if object.kind_of/instance_of statements to check and raise runtime errors everywhere, which is ugly. …

Read More
How to check if a value exists in an array in Ruby

I have a value 'Dog' and an array ['Cat', 'Dog', 'Bird']. How do I check if it exists in the array without looping through it? Is there a simple way of checking if the value exists, nothing more?

Read More
How to write a switch statement in Ruby

How do I write a switch statement in Ruby?

Read More