Published Jan 08 2021
We’ve previously seen how to create a nested function in Python.
If you return a nested function from a function, that nested function has access to the variables defined in that function, even if that function is not active any more.
Here is a simple counter example.
def counter(): count = 0 def increment(): nonlocal count count = count + 1 return count return increment increment = counter() print(increment()) # 1 print(increment()) # 2 print(increment()) # 3
We return the
increment() inner function, and that has still access to the state of the
count variable even though the
counter() function has ended.
I wrote an entire book on this topic 👇