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César Jardim
4,847 PointsWhy do you use self.start_time in the summary method but NOT self.question_start in the ask method?
In this video I don't understand why you need to reference it as being self.start_time if it isn't an attribute of the class.
César Jardim
4,847 PointsBrendan Whiting - Updated the question to include the link to the video. Minute 1:57 :)
1 Answer
Chris Freeman
Treehouse Moderator 68,468 PointsKenneth uses the phrase "We need to remember to hold on the that...." at various points in the video. To hold on to something, that is, make it persistent, it needs to be assigned to an attribute. In the ask() method, question_start is not needed beyond the return of the method so it's defined as a local variable.
In the summary() method, he does want to hold on to it, so he makes it persistent by making it an attribute using "self."
He could have used self.question_start but it's best to use a local variable if possible.
César Jardim
4,847 PointsChris Freeman, thanks for your answer! Let me double check if I get it: essentially by making it self.variable_name you're making it a global variable for that class?
Chris Freeman
Treehouse Moderator 68,468 PointsCésar, "global variable" is too broad of a term. It's more like a "local variable" (known as an attribute) that is bound to a class instance. A true local variable in a class object is typically a variable that is not an class attribute such as an intermediate result in a method. All methods within that class instance can reference these attribute using the self. prefix which represents the current instance of that class.
Brendan Whiting
Front End Web Development Techdegree Graduate 84,738 PointsBrendan Whiting
Front End Web Development Techdegree Graduate 84,738 PointsWhat challenge or video?