Question

Given below example, I want to figure out what causes the exception of
"NameError: global name 'MATRIX' is not defined" when executing test.fun1().

Thanks a lot.

class test:
    MATRIX = []

    @staticmethod        
    def fun1():
        global MATRIX
        test.fun2(MATRIX)

    @staticmethod
    def fun2(MATRIX):
        MATRIX.append(2)

test.fun1()    
print test.MATRIX

Answer 1

Your MATRIX is not global, it’s a class attribute, try like this:

class test:
    MATRIX = []

    @classmethod     # Note classmethod, not staticmethod   
    def fun1(cls):   # cls will be test here
        test.fun2(cls.MATRIX)

    @staticmethod
    def fun2(MATRIX):
        MATRIX.append(2)

test.fun1()    
print test.MATRIX