Python: Modify Global list inside a function

Question

First of all, I understand that I can use global statement to access global variables. But somehow I was able to modify a global list without global

Answer 1

There are two reasons for this result:

1. Variables are simply names that refer to objects
2. List is mutable

In func1,nums refer to a new object because a new list is created. Therefore global nums is not affected.

In func2, the modification is applied to the object passed in. Thus global nums is changed. A new object is not created because list is mutable.

ref: https://docs.python.org/3/faq/programming.html#what-are-the-rules-for-local-and-global-variables-in-python