global variable not assigned, newbie question

[Jean-Daniel Gamache]

Hi! here's a python newbie question ...
why is my variable (myNum) not assigned the value 10 ???

========

myNum = 0

def setNum():
myNum = 10
print myNum

def main():
setNum()
print myNum

if __name__ == '__main__':
main()

 

[Diez B. Roggisch]

You need myNum to be declared global:

def setNum():
global myNum
myNum = 10
print myNum

Apart from that, its usually considered bad style using global variables -
better use this:

def calcNum():
myNum = 10
return myNum

myNum = calcNum()

 

[Peter Hansen]

Hi! here's a python newbie question ...
why is my variable (myNum) not assigned the value 10 ???

[snip example]

http://www.python.org/doc/faq/programming.html#how-do-you-set-a-global-variable-in-a-function

This and many other questions are answered in the Frequently
Asked Questions (FAQ) list.

Also make sure you've read the tutorial
http://docs.python.org/tut/tut.html as it (I expect) would
answer that question as well.

-Peter