> By the way, this is an important and fundamental subject about > Python. When I teach classes on Python, I always need to explain > Python's execution model, and I always struggle with it. So, > anything you can tell me that would help me teach this will be much > appreciated. > > Dave
The way I keep it clear is simple. If python needs the value of the name (it has to look it up) then it had better be defined. Otherwise ~ It doesn't matter! Think of it like assignment. x = 1 Does python need to know the current value of x? No. Then x does not have to be previously defined. f() Does python need to know the current value of f? Yes. It has to know that f is a function, and where the address is, etc. def f1(): f() Does python need to know the current value of f? No. Not until f1 is executed. Does this help? Only one rule to remember. ;-) ~Does python need to know the value of _this_ variable?~ JS _______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
