Comment by bobbylarrybobby
12 days ago
Naively I would expect that each iteration of a for loop creates a new loop variable (all with the same name, but effectively each in their own scope) and so each closure holds a reference to a variable named number whose value never changes, and there is a distinct one of these number variables per closure .
That is not how variables in Python work. Variable assignment is just name binding. This is clearly mentioned in every Python beginner tutorial I know of. Python code is a script. Follow the script and you know what Python does (with only a few exceptions, see e.g. below).
About the scope: Python knows in principal only 2 scopes: local and global. If you define a function (or a class) Python creates a new emtpy/filled with the function arguments local scope (system table). That gets filled successively by local variable assignments etc. There happens a little bit of magic: if you use a variable of the next higher scope, it gets copied (!) to the local scope. You can follow that easily by print(locals()). (You can also use the global scope, but that is another topic).
Edit: had to clarify some points