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Michael Vilabrera
Courses Plus Student 11,252 PointsDifference between an instance variable and property
I have a belief that properties were meant to replace instance variables, however I have seen code where developers use both together. Would someone detail when or why one is preferred over the other?
3 Answers
Amit Bijlani
Treehouse Guest TeacherThe Understanding property video should help.
Michael Vilabrera
Courses Plus Student 11,252 PointsThank you, Amit! I guess to clarify my question is: are instance variables declared in the implementation more secure, or are they faster? From what I gather after watching the video is that properties lessen the need to declare instance variables. However when programmers use them both, it does not make sense. They could just use properties exclusively.
Amit Bijlani
Treehouse Guest TeacherIt's not that a property lessens the need for instance variables. When you declare a property an instance variable along with getter/setter methods are created for you automatically. So there is an instance variable which is usually prefixed with an underscore. For example, you created a property named titles then there is an instance variable created for you named _titles. Think of property a shortcut way of defining instance variables that need getter/setter methods to be accessed. The only other reason you would not want to use properties would be to use an instance variable that is only used within the class and not outside of it.
Michael Vilabrera
Courses Plus Student 11,252 PointsThanks Amit that helped very much!