原代码:
bug_cnt=0
def foo():
for i in range(10):
bug_cnt = bug_cnt+1
if __name__ == '__main__':
foo()
print bug_cnt
运行出现“local variable 'bug_cnt' referenced before assignment”错误。
修改添加关键字global。
bug_cnt=0
def foo():
global bug_cnt
for i in range(10):
bug_cnt = bug_cnt+1
if __name__ == '__main__':
foo()
print bug_cnt
成功打印数字10.