Close script from another script

[deanhystad]

In Python each code file is a "module". Modules each have a namespace. You can access these variables if you have access to their namespace. When you do "import module" you are gaining access to the module's namespace.

I have three files;
test1.py:

x = 10

def printx():
    print(x)

test2.py

import test1

def printx():
    print(test1.x)

def setx(value):
    test1.x = value

test3.py

import math
import test1
import test2
from test1 import x

print(x, test1.x)
test1.printx()
test2.printx()

print('test2.setx(42)')
test2.setx(42)
print(x, test1.x)
test1.printx()
test2.printx()

print('test1.x = PI')
test1.x = 'PI'
print(x, test1.x)
test1.printx()
test2.printx()

print('x = math.pi')
test1.x = math.pi
print(x, test1.x)
test1.printx()
test2.printx()

When I execute test3.py I get this:

Output:
========== RESTART: C:\Users\hystadd\Documents\python\sandbox\junk.py ==========
10 10
10
10
test2.setx(42)
10 42
42
42
test1.x = PI
10 PI
PI
PI
x = math.pi
10 3.141592653589793
3.141592653589793
3.141592653589793

Notice that I can set the value of test1.py from modules test1, test2 or test3. When I change the value of test1.x the change can be seen in test1, test2 and test3.

Also notice that "from test1 import x' does not work the same as explicitly using the namespace (test1.x). It would appear that "from test1 import x" creates a new variable in the current module's namespace. This was verified by checking the variable id.

Output:
>>> id(x)
140721929705408
>>> id(test1.x)
2714390832848

This could be an issue if you use from..import.. and expect to be able to change an immutable variable.