Simple example:
class A end class B < A end Then, how can I judge whether class B is inherited from class A? Is there a method somehow like is_a? or maybe called is_child_of??
I can't find one.
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3 Answers
You can use the < operator:
B < A will be true, if B is a subclass of A.
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In Ruby the class Object has a kind_of? method that does what you want. This is also aliased to is_a?:
module M; end class A include M end class B < A; end class C < B; end b = B.new b.kind_of? A #=> true b.is_of? B #=> true b.kind_of? C #=> false b.kind_of? M #=> true Also, the class Class has a superclass method:
>> B.superclass => A Note that you can find out what methods any object supports by asking it:
B.methods.sort The output from this command would have included the kind_of?/is_a?/superclass methods.
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You can find all the method definitions for Ruby Objects online.
The closest useful method would be is_a? or kind_of? however read the documentation to be sure they are what you're looking for.
