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Hossam Khalifa
17,200 PointsAttr_writer vs attr_reader
When setting an attr_reader it can be used within methods without the '@' symobl to get the value.
But when I try to set the value if something is set as an attr_writer the '@' must be used to set the value or it will not work. Example
Class SomeThing
attr_accessor :name
def initialize(name)
@name = name
end
def getName?
name # This will return the name
end
#but this will not set the name
def setName!(new_name)
name = new_name
end
end
Can someone explain why Or tell me if I am mistaking Thank you Jason Seifer please answer
2 Answers
Brandon Barrette
20,485 PointsInside the initialize, from what I understand, you must use the @ since it's an instance variable (initializing an instance of the class). In other methods you write, you wouldn't need the @ if it's an attr_reader, attr_writer, or attr_accessor.
Hossam Khalifa
17,200 PointsI don't think you get me! It works with attr_reader But not with attr_writer My question is why??
Hossam Khalifa
17,200 PointsI don't think you get me! It works with attr_reader But not with attr_writer My question is why??
Jason Seifer
Treehouse Guest TeacherHi Hossam Khalifa, great question!
When you do the attr_writer method, it is the equivalent of writing the following method:
def name=(new_name)
@name = new_name
end
You would the refer to this elsewhere in your code as the following:
def some_method
self.name = "Hossam"
end
This is necessary or, as Jessica Hori said, Ruby will attempt to access a local variable rather than a global one. Hope that helps!
Jessica H
16,612 PointsJessica H
16,612 PointsBy making @ variable, you are thus making name available throughout the class by other methods..
If you don't have an @ sign, the variable will only "local" and can only be used by the method in which you are defining it.