Global Name 'q' not Defined - Python

Question

I have a program like :

class ABC: q = {} def update: self.state = (xx,xx) global q if self.state in q: // do something

I am getting the error :

"NameError: global name 'q' is not defined"

Im new to python and need some help.

Your code is not valid python, so it is difficult to gauge what your intent is here. — Paul Rooney
– Paul Rooney, Commented Sep 26, 2016 at 3:02

Raymond Hettinger · Accepted Answer · 2016-09-26 03:04:34Z

You can move q outside of the class:

q = {} class ABC: def update: self.state = (xx,xx) global q if self.state in q: # do something pass

or you can reference q as a class variable:

class ABC: q = {} def update: self.state = (xx,xx) if self.state in ABC.q: # do something pass

ooh, Thanks Raymond, i think i get it. but why would i choose one over the other?

Amber · Accepted Answer · 2016-09-26 02:58:20Z

q isn't being declared as a global variable here - it's being declared as a class variable of class ABC.

If you want q to be global, you should define it before you start declaring the class.

2 Answers 2