day15-python之变量和递归

1.局部变量与全局变量

#!/usr/bin/env python
# -*- coding:utf-8 -*-

# name='lhf'
# def change_name():
#     global name
#     name='帅了一比'
#     print('change_name',name)
#
#
# change_name()
# print(name)

# name='lhf'
#
# def change_name():
#     name1='帅了一比'
#     name2='帅了一比'
#     name3='帅了一比'
#     print('change_name',name)
#
# globals

# NAME = "杠娘"
#
# def yangjian():
#     global NAME
#     NAME = "小东北"
#     print('我要搞', NAME)
#
# def qupengfei():
#     NAME = "基"
#     print('我要搞', NAME)
#
# yangjian()
# qupengfei()

# NAME = "产品经理"
#
# def yangjian():
#     # NAME = "史正文"
#     global NAME # 已经声明，ＮＡＭＥ就是全局的的那个变量
#     print('我要搞', NAME)
#     NAME = "小东北"  # 修改 全局的变量
#     print('我要搞', NAME)
#
# def qupengfei():
#     NAME = "基"
#     print('我要搞', NAME)

# 如果函数的内容无global关键字，
#   - 有声明局部变量
# NAME = ["产品经理","廖波湿"]
# def qupengfei():
#     NAME = "自己"
#     print('我要搞', NAME)
# qupengfei()
#   - 无声明局部变量
# NAME = ["产品经理","廖波湿"]
# def qupengfei():
#     NAME.append('XXOO')
#     print('我要搞', NAME)
# qupengfei()

# 如果函数的内容有global关键字
#   - 有声明局部变量
# NAME = ["产品经理","廖波湿"]
# def qupengfei():
#     global NAME
#     NAME = "自己"
#     print('我要搞', NAME)
# qupengfei()
        # 错误示例
# NAME = ["产品经理","廖波湿"]
# def qupengfei():
#     NAME = "自己"
#     global NAME
#     print('我要搞', NAME)
# qupengfei()
#   - 无声明局部变量
# NAME = ["产品经理","廖波湿"]
# def qupengfei():
#     global NAME
#     NAME = ["阿毛"]
#     NAME.append('XXOO')
#     print('我要搞', NAME)
# qupengfei()

######## 全局变量变量名大写
######## 局部变量变量名小写

# 优先读取局部变量，能读取全局变量，无法对全局变量重新赋值 NAME=“fff”，
#     但是对于可变类型，可以对内部元素进行操作
# 如果函数中有global关键字，变量本质上就是全局的那个变量，可读取可赋值 NAME=“fff”
# qupengfei()
# yangjian()

# NAME = ["产品经理","廖波湿"]
#
# def yangjian():
#     # NAME = "史正文"
#     global NAME # 已经声明，ＮＡＭＥ就是全局的的那个变量
#     print('我要搞', NAME)
#     NAME = "小东北"  # 修改 全局的变量
#     print('我要搞', NAME)
#
# def qupengfei():
#     # NAME = "aS"
#     NAME.append('天扎龙')
#     print('我要搞', NAME)
#
# yangjian()

# NAME = ["产品经理","廖波湿"]
# def qupengfei():
#     name = "自己"
#     global NAME
#     print('我要搞', NAME)
# qupengfei()

# NAME = '海风'
#
# def huangwei():
#     name = "黄伟"
#     print(name)
#     def liuyang():
#         name = "刘洋"
#         print(name)
#         def nulige():
#             name = '沪指花'
#             print(name)
#         print(name)
#         nulige()
#     liuyang()
#     print(name)
#
# huangwei()  # 黄伟 刘洋 刘洋 沪指花 黄伟

# name = "刚娘"
# 
# def weihou():
#     name = "陈卓"
#     def weiweihou():
#         nonlocal name   # nonlocal，指定上一级变量，如果没有就继续往上直到找到为止
#         name = "冷静"
# 
#     weiweihou()
#     print(name)
# 
# print(name)
# weihou()
# print(name)
# 刚娘
# 冷静
# 刚娘

2.前向引用

#!/usr/bin/env python
# -*- coding:utf-8 -*-


# def foo():
#     print('from foo')
#     bar()
#
# foo()

# def bar():
#     print('from bar')
# def foo():
#     print('from foo')
#     bar()
#
# foo()



# def foo():
#     print('from foo')
#     bar()
#
# def bar():
#     print('from bar')
# foo()

# def foo():
#     print('from foo')
#     bar()
# 
# foo()
# 
# def bar():
#     print('from bar')

3.测试

#!/usr/bin/env python
# -*- coding:utf-8 -*-
name='海风'
def huangwei():
    name = "黄伟"
    print(name)
    def liuyang():
        name = "刘洋"
        print(name)
        def nulige():
            name = '炉指花'
            print(name)
        print(name)
        nulige()
    liuyang()
    print(name)

print(name)
huangwei()
print(name)  # 海风 黄伟 刘洋 刘洋 炉指花 黄伟 海风

#!/usr/bin/env python
# -*- coding:utf-8 -*-
def calc(n):
    print(n)
    if int(n / 2) == 0: # 10/2  5/2  2/2
        return n
    res=calc(int(n / 2))
    return res


calc(10)#   10 5 2 1

4.递归

#!/usr/bin/env python
# -*- coding:utf-8 -*-
# def calc(n):
#     print(n)
#     if int(n / 2) == 0:
#         return n
#     res=calc(int(n / 2))
#     return res
#
#
# res=calc(10)
# print(res)

# while True:
#     print(10)

# import time
#
# person_list=['alex','wupeiqi','linhaifeng','zsc']
# def ask_way(person_list):
#     print('-'*60)
#     if len(person_list) == 0:
#         return '根本没人知道'
#     person=person_list.pop(0)
#     if person == 'linhaifeng':
#         return '%s说:我知道,老男孩就在沙河汇德商厦,下地铁就是' %person
#
#     print('hi 美男[%s],敢问路在何方' % person)
#     print('%s回答道:我不知道,但念你慧眼识猪,你等着,我帮你问问%s...' % (person, person_list))
#     time.sleep(1)
#     res=ask_way(person_list)
#
#
#     print('%s问的结果是: %res' %(person,res))
#     return res
#
# res=ask_way(person_list)
# print(res)
# 我          来英                杨建         是征文
# res等沙河      res等沙河       res等 沙河      return ‘沙河’
#                 print          printres


import time
res=time.sleep(10)
print('----------->')