python - Problem with variable scope in different files

Question

Now there are two files:

a.py:

x=1
from b import *
printx()

b.py:

def printx():
    print(x)

When calling $ python3 a.py from the command line, there will be a NameError. I don’t understand here. When calling a.py directly, isn’t x considered a global variable? According to the LEGB rules, why does it go wrong?

Answer 1

x is only visible in file a. Importing b in file a only makes the method printx in file b visible to file a. You can call it, and it does not change the invisibility of file x to file b. .