On 23/04/19 3:40 PM, Steven D'Aprano wrote:
Watch out here, you have a mutable default value, that probably doesn't work the way you expect. The default value is created ONCE, and then shared, so if you do this:a = MyCustomList() # Use the default list. b = MyCustomList() # Shares the same default list! a.append(1) print(b.list) # prints [1] You probably want: def __init__(self, list=None): if list is None: list = [] self.list = list
That is really a new thing to me. I didn't know. Why list=None in the parameter list is different than in the body of __init__ method? Can you elaborate this?
-- Thanks, Arup Rakshit _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
