多级菜单
- 多级菜单
- 可依次选择进入各子菜单
- 所需新知识点：列表、字典
#!/usr/bin/env python
# -*- coding: utf-8 -*-
menu = {
‘北京‘:{
‘海淀‘:{
‘五道口‘:{
‘soho‘:{},
‘网易‘:{},
‘google‘:{}
},
‘中关村‘:{
‘爱奇艺‘:{},
‘汽车之家‘:{},
‘youku‘:{},
},
‘上地‘:{
‘百度‘:{},
},
},
‘昌平‘:{
‘沙河‘:{
‘老男孩‘:{},
‘北航‘:{},
},
‘天通苑‘:{},
‘回龙观‘:{},
},
‘朝阳‘:{},
‘东城‘:{},
},
‘上海‘:{
‘闵行‘:{
"人民广场":{
‘炸鸡店‘:{}
}
},
‘闸北‘:{
‘火车战‘:{
‘携程‘:{}
}
},
‘浦东‘:{},
},
‘山东‘:{},
}
current_level = menu
last_level = []
while True:
for key in current_level:
print(key)
choice = input(">>:").strip()
if len(choice) ==0:break
if choice ==‘b‘:
if len(last_level)==0:break
current_level = last_level[-1]
last_level.pop()
if choice not in current_level:continue
last_level.append(current_level)
current_level = current_level[choice]
字典
查询
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
print(dic[‘name‘])
print(dic.get(‘namedf‘))#用get，如果没有这个值，查询不会报错
以上代码运行结果
alex None
add
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
dic[‘gender‘]=‘female‘
print(dic)#打印字典是无序的
以上代码运行结果
{‘age‘: 18, ‘gender‘: ‘female‘, ‘name‘: ‘alex‘}
change
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
dic[‘name‘]=‘lhf‘
print(dic)
以上代码运行结果
{‘name‘: ‘lhf‘, ‘age‘: 18}
del
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
del dic[‘name‘]
print(dic)
以上代码运行结果
{‘age‘: 18}
字典里嵌入其它数据类型
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic1={
1:‘alex‘,
‘name‘:‘lhf‘,
(1,2,3):{‘age‘:18},
‘name‘:‘alex‘
}
print(dic1[1])
print(dic1[‘name‘])
print(dic1[(1,2,3)])
print(dic1[(1,2,3)][‘age‘])
以上代码运行结果
alex
alex
{‘age‘: 18}
18
字典的其它用法
#!/usr/bin/env python # -*- coding: utf-8 -*- dic1=dict.fromkeys(‘abc‘,1) print(dic1)
以上代码运行结果（注意：此处类似浅拷贝）
{‘b‘: 1, ‘c‘: 1, ‘a‘: 1}
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
dic2 =dict.fromkeys([‘a‘,‘b‘],1)
print(dic2)
print(dic.get(‘name‘))
以上代码运行结果
{‘b‘: 1, ‘a‘: 1}
alex
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
for k,v in dic.items():
print(k,v)
print(dic.keys())
for i in dic.keys():
print(‘key is %s,value is %s‘%(i,dic[i]))
以上代码运行结果
age 18 name alex dict_keys([‘age‘, ‘name‘]) key is age,value is 18 key is name,value is alex
指定删除
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
dic.pop(‘name‘)
print(dic)
以上代码运行结果
{‘age‘: 18}
随机删除
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
dic.popitem()
print(dic)
以上代码运行结果
{‘name‘: ‘alex‘}
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
dic.setdefault(‘gender‘,[]).append(‘male‘)
dic[‘gender‘].append(‘female‘)
以上代码运行结果
{‘age‘: 18, ‘name‘: ‘alex‘, ‘gender‘: [‘male‘, ‘female‘]}
__author__ = "zhou"
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
dic1 = {‘gender‘:‘male‘,‘name‘:‘ldf‘}
dic.update(dic1)
print(dic)
以上代码运行结果
{‘name‘: ‘ldf‘, ‘age‘: 18, ‘gender‘: ‘male‘}
常用的取字典里面键值的方法
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic={‘name‘:‘alex‘,‘age‘:18}
for k in dic:
print(k,dic[k])
for i in dic.values():
print(i)
以上代码运行结果
age 18 name alex 18 alex
浅拷贝
#!/usr/bin/env python
# -*- coding: utf-8 -*-
dic ={‘name‘:‘alex‘,‘age‘:18,‘gfs‘:["Monkey","Cythrina","Rachel"]}
dic2=dic.copy()
print(dic)
print(dic2)
dic2["name"]="Jack"
dic2["gfs"][2] = "hhhh"
print(dic)
print(dic2)
以上代码运行结果
{‘gfs‘: [‘Monkey‘, ‘Cythrina‘, ‘Rachel‘], ‘name‘: ‘alex‘, ‘age‘: 18}
{‘gfs‘: [‘Monkey‘, ‘Cythrina‘, ‘Rachel‘], ‘name‘: ‘alex‘, ‘age‘: 18}
{‘gfs‘: [‘Monkey‘, ‘Cythrina‘, ‘hhhh‘], ‘name‘: ‘alex‘, ‘age‘: 18}
{‘gfs‘: [‘Monkey‘, ‘Cythrina‘, ‘hhhh‘], ‘name‘: ‘Jack‘, ‘age‘: 18}
集合
字符编码
字符---gb2313--->硬盘硬盘---gb2313--->字符字符 --->unicode--->内存 1、内存固定使用unicode编码，硬盘的编码（即你可以修改的软件编码）2、使用什么编码往硬盘存，就用什么编码去读3、程序运行分两阶段： 1、从硬盘读到内存 2、python解释器运行已经读到内存的代码4、针对一个test.py文件来说python与nodpad++\vim区别是多了第二步。
时间： 2024-08-03 09:53:09