Python 全局未按预期运行

Question

下面的打印出"None"而不是"whatever"。我不明白为什么。

dirr = None
def method():
    global dirr # you have to declare that you'll use global variable 'dirr'
    dirr = "whatever"
print `dirr`

Answer 1

你应该调用'method'一次。

dirr = None
def method():
    global dirr # you have to declare that you'll use global variable 'dirr'
    dirr = "whatever"
method()
print (dirr)

结果是：

whatever