Compare this, without using nonlocal: x = 0 def outer(): x = 1 def inner(): x = 2 print(“inner:”, x) inner() print(“outer:”, x) outer() print(“global:”, x) # inner: 2 # outer: 1 # global: 0 To this, using nonlocal, where inner()‘s x is now also outer()‘s x: x = 0 def outer(): x = 1 … Read more
Inner functions can read nonlocal variables in 2.x, just not rebind them. This is annoying, but you can work around it. Just create a dictionary, and store your data as elements therein. Inner functions are not prohibited from mutating the objects that nonlocal variables refer to. To use the example from Wikipedia: def outer(): d … Read more
On Python 3, use the nonlocal keyword: The nonlocal statement causes the listed identifiers to refer to previously bound variables in the nearest enclosing scope excluding globals. This is important because the default behavior for binding is to search the local namespace first. The statement allows encapsulated code to rebind variables outside of the local … Read more
Compare this, without using nonlocal: x = 0 def outer(): x = 1 def inner(): x = 2 print(“inner:”, x) inner() print(“outer:”, x) outer() print(“global:”, x) # inner: 2 # outer: 1 # global: 0 To this, using nonlocal, where inner()‘s x is now also outer()‘s x: x = 0 def outer(): x = 1 … Read more