Python Programming Language :: function in a function accessing vars


	function in a function accessing vars Hi all, I wanted to solve a small problem, and I have a function that is typically meant only as a function belonging inside another function. >From the inner function I want to access a variable from the outer function like; def A(): some_var = 1 def B(): some_var += 1 B() But this does not work, the function B does not recognize the some_var. In my mind I thought the scope would propagate to the new function and the vars would still be accessible. How can I go about this? With regards - Jorgen - Hide quoted text - Jorgen Bodde wrote: > Hi all, > I wanted to solve a small problem, and I have a function that is > typically meant only as a function belonging inside another function. >>From the inner function I want to access a variable from the outer > function like; > def A(): > some_var = 1 > def B(): > some_var += 1 > B() > But this does not work, the function B does not recognize the > some_var. In my mind I thought the scope would propagate to the new > function and the vars would still be accessible. > How can I go about this? The problem here is the way python determines which variables are local to a function - by inspecting left sides. I'm not sure if there are any fancy inspection/stackframe/cells-hacks to accomplish what you want. But the easiest solution seems to be a (admittedly not too beautiful) def A(): some_var = [1] def B(v): v[0] += 1 B(some_var) Or you should consider making A a callable class and thus an instance, and some_var an instance variable. Always remember: "a closure is a poor persons object, and an object is a poor mans closure" Diez Hi Diez, Thanks, I thought it worked similar to C++ where a higher compound could access a lower section. But as it is not straight forward, I think it is better to embed the functionality inside a class, and make it a member variable .. now why didn't I think of that ;-) Thanks, - Jorgen On 6/6/07, Diez B. Roggisch <d@nospam.web.de> wrote: - Hide quoted text - > Jorgen Bodde wrote: > > Hi all, > > I wanted to solve a small problem, and I have a function that is > > typically meant only as a function belonging inside another function. > >>From the inner function I want to access a variable from the outer > > function like; > > def A(): > > some_var = 1 > > def B(): > > some_var += 1 > > B() > > But this does not work, the function B does not recognize the > > some_var. In my mind I thought the scope would propagate to the new > > function and the vars would still be accessible. > > How can I go about this? > The problem here is the way python determines which variables are local to a > function - by inspecting left sides. > I'm not sure if there are any fancy inspection/stackframe/cells-hacks to > accomplish what you want. But the easiest solution seems to be a > (admittedly not too beautiful) > def A(): > some_var = [1] > def B(v): > v[0] += 1 > B(some_var) > Or you should consider making A a callable class and thus an instance, and > some_var an instance variable. Always remember: "a closure is a poor > persons object, and an object is a poor mans closure" > Diez > -- > http://mail.python.org/mailman/listinfo/python-list On Jun 6, 6:40 am, "Jorgen Bodde" <jorgen.maill@gmail.com> wrote: > Hi Diez, > Thanks, I thought it worked similar to C++ where a higher compound > could access a lower section. It can 'access a lower section'; what it can't do is change that 'lower section'; in your example case with an int, this matters because ints are immutable. Lists, on the other hand, are mutable. You can access the methods of the list that mutate it. You're always working with the same list, but it has different contents when you mutate it. - Hide quoted text - > But as it is not straight forward, I > think it is better to embed the functionality inside a class, and make > it a member variable .. now why didn't I think of that ;-)