Python非本地语句 [英] Python nonlocal statement

问题描述

Python nonlocal 语句做什么（在Python 3.0及更高版本中）？

What does the Python nonlocal statement do (in Python 3.0 and later)?

官方Python网站上没有文档， help（nonlocal） / p>

There's no documentation on the official Python website and help("nonlocal") does not work, either.

推荐答案

比较，不使用 nonlocal ：

x = 0
def outer():
    x = 1
    def inner():
        x = 2
        print("inner:", x)

    inner()
    print("outer:", x)

outer()
print("global:", x)

# inner: 2
# outer: 1
# global: 0

使用 nonlocal c> inner（）' x 现在也是 outer（） code> x ：

To this, using nonlocal, where inner()'s x is now also outer()'s x:

x = 0
def outer():
    x = 1
    def inner():
        nonlocal x
        x = 2
        print("inner:", x)

    inner()
    print("outer:", x)

outer()
print("global:", x)

# inner: 2
# outer: 2
# global: 0

如果我们使用 global ，它会将 x 全局值：

x = 0
def outer():
    x = 1
    def inner():
        global x
        x = 2
        print("inner:", x)

    inner()
    print("outer:", x)

outer()
print("global:", x)

# inner: 2
# outer: 1
# global: 2

这篇关于Python非本地语句的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！