全球没有像我想的那样工作

Question

我无法理解为什么全局变量不起作用。

global globalvar
globalvar = 0
def print_globalvar():
        globalvar = globalvar + 1
        print globalvar

def print_var():
        print_globalvar()
        globalvar = 10
        print_globalvar()

print_var()

上述代码的回溯。

Traceback (most recent call last):
  File "test.py", line 14, in <module>
    print_var()
  File "test.py", line 9, in print_var
    print_globalvar()
  File "test.py", line 5, in print_globalvar
    globalvar = globalvar + 1
UnboundLocalError: local variable 'globalvar' referenced before assignment