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Defining an Uninitialized Instance Variable
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Defining an Uninitialized Instance Variable
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Is it elegant to use instance variables in a class which are not initialized and setting them using other methods? Or maybe there is a better way to do that?
class Klass
def initialize(a)
@a = a
end
def set_b(b)
@b = b
end
end
In contrast to other languages, If you do not initialize an instance variable it will always be nil (whereas in certain other languages you could get something undefined).
As long as other methods of Klass do not depend on the instance variable actually having a value, this should be ok.
As for getters and setters, there are attr_accessor, attr_reader and attr_writer (see the docs).
class Klass
attr_accessor :b
# there's also attr_reader and attr_writer
def initialize(a)
@a = a
end
end
k = Klass.new :foo
k.b = :bar
k.b
#=> :bar
k.a
#=> undefined method `a' for #<Klass:0x007f842a17c0e0 @a=:foo, @b=:bar> (NoMethodError)
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