上节作业回顾(讲解+温习90分钟)

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# author:Mr.chen
# 仅用列表+循环实现“简单的购物车程序” import os,time goods = [("苹果",300),("白菜",400),("鸭梨",1000),("柿子",3000),("芒果",5000),("桂圆",8000)]
Tag = True
buy_List = [] while Tag :
os.system("clear")
salary = input("请输入你的工资(输入q退出程序):")
if salary == "q" or salary == "Q" :
print ("您并未购买商品,程序退出!")
exit()
elif salary.isdigit() :
salary = int(salary)
break
else :
print ("请以数字的形式输入您的工资!")
time.sleep(1.5) while Tag :
os.system("clear")
title = "《商品清单》 您的余额为:{}元".format(salary)
print (title)
for item in goods :
print (goods.index(item)+1,item[0],item[1])
while Tag :
num = input("请输入想要购买的商品的编号(输入q退出程序并结帐):")
if num == "q" or num == "Q" :
if len(buy_List) == 0 :
print ("您没有买任何东西,程序退出!")
exit()
else :
for index in buy_List :
print ("您购买了一件{}商品,价格为:{}".format(goods[index-1][0],goods[index-1][1]))
else :
print ("您的最后余额为{}元,程序退出!".format(salary))
exit()
elif num.isdigit() and int(num) <= len(goods) and int(num) != 0 :
num = int(num)
break
else :
print ("请输入正确的数字编号,只能单选!")
while Tag :
if salary < goods[num-1][1] :
print ("您的余额已不足,请重新选择商品!")
time.sleep(1.5)
break
else :
salary = salary - goods[num-1][1]
buy_List.append(num)
print ("{}商品购买成功!您的余额为{}元".format(goods[num-1][0],salary))
time.sleep(1.5)
break

一,Python3 入门知识补充

1.1 bytes类型

Python运维开发基础04-语法基础-LMLPHP

#在Python3中,字符串和二进制可以相互转换

>>> "你好吗?".encode()         #将字符串转换成二进制
b'\xe4\xbd\xa0\xe5\xa5\xbd\xe5\x90\x97\xef\xbc\x9f'
>>> "你好吗?".encode().decode() #将二进制转换成字符串
'你好吗?'

1.2 三元运算

#正常写法
>>> a,b,c
(1, 3, 5)
>>> if a > b : c = a
... else : c = b
...
>>> c
3 #三元运算写法 >>> a,b,c = 1,3,5
>>> d = a if a > b else c #如果a大于b,那么d = a 否则的话,d = c
>>> d
5

1.3 进制

  • 二进制:01
  • 八进制:01234567
  • 十进制:0123456789
  • 十六进制:0123456789ABCDEF

二进制与十六进制之间的进制转换

http://jingyan.baidu.com/album/47a29f24292608c0142399cb.html?picindex=1

计算机内存地址和为什么用16进制?

二,字典

语法:

info = {
'stu1101':"TengLan Wu",
'stu1102':"LongZe Luola",
'stu11103':"XiaoZe Maliya",
}

字典的特性:

  • dict是无序的
  • key必须是唯一的(不能重复)

2.1 增加

#代码演示

>>> Dict = {'stu1101':"yunjisuan","stu1102":"benet","stu1103":"Tom","stu1104":"Amy"}
>>> Dict["stu1105"] = "苍井空"
>>> Dict
{'stu1102': 'benet', 'stu1104': 'Amy', 'stu1105': '苍井空', 'stu1101': 'yunjisuan', 'stu1103': 'Tom'}

2.2 修改

#代码演示

>>> Dict = {'stu1101':"yunjisuan","stu1102":"benet","stu1103":"Tom","stu1104":"Amy"}
>>> Dict["stu1102"] = "武藤兰"
>>> Dict
{'stu1102': '武藤兰', 'stu1104': 'Amy', 'stu1101': 'yunjisuan', 'stu1103': 'Tom'}

2.3 删除

(1)指定key值进行删除

#代码演示:

>>> Dict = {"stu1101":"Tom","stu1102":"Amy","stu1103":"feixue","stu1104":"zhangsan","stu1105":"lisi"}
>>> Dict
{'stu1101': 'Tom', 'stu1103': 'feixue', 'stu1104': 'zhangsan', 'stu1105': 'lisi', 'stu1102': 'Amy'}
>>> Dict.pop("stu1101") #删除指定key,key所对应的value作为返回值(标准用法)
'Tom'
>>> Dict
{'stu1103': 'feixue', 'stu1104': 'zhangsan', 'stu1105': 'lisi', 'stu1102': 'Amy'}
>>> del Dict["stu1104"] #删除指定key,无返回值
>>> Dict
{'stu1103': 'feixue', 'stu1105': 'lisi', 'stu1102': 'Amy'}

(2)删除整个字典

#代码演示:

>>> Dict = {"stu1101":"Tom","stu1102":"Amy","stu1103":"feixue","stu1104":"zhangsan","stu1105":"lisi"}
>>> Dict
{'stu1101': 'Tom', 'stu1103': 'feixue', 'stu1104': 'zhangsan', 'stu1105': 'lisi', 'stu1102': 'Amy'}
>>> del Dict
>>> Dict #字典全被删除,所以找不到了
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'Dict' is not defined

(3)随机删除字典的key:value,并将删除的key:value作为返回值

#代码演示:

>>> Dict = {"stu1101":"Tom","stu1102":"Amy","stu1103":"feixue","stu1104":"zhangsan","stu1105":"lisi"}
>>> Dict.popitem()
('stu1101', 'Tom')
>>> Dict.popitem()
('stu1103', 'feixue')
>>> Dict.popitem()
('stu1104', 'zhangsan')
>>> Dict
{'stu1105': 'lisi', 'stu1102': 'Amy'}

2.4 查找

#代码演示:

>>> Dict = {"stu1101":"Tom","stu1102":"Amy","stu1103":"feixue","stu1104":"zhangsan","stu1105":"lisi"}
>>> "stu1102" in Dict #标准用法
True
>>> Dict.get("stu1102") #获取value
'Amy'
>>> Dict["stu1102"] #也是获取value,但是看下面
'Amy'
>>> Dict["stu1108"] #当字典中没有该key,会报错
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
KeyError: 'stu1108'
>>> Dict.get("stu1108") #get()找不到key不会报错。

2.5 提取字典里所有的keys

#代码演示:

>>> Dict = {"stu1101":"Tom","stu1102":"Amy","stu1103":"feixue","stu1104":"zhangsan","stu1105":"lisi"}
>>> "stu1101" in Dict #可以直接判断字符串是否在一个字典的keys中
True
>>> Dict.keys() #提取字典所有的keys,返回一个字典类型的keys列表
dict_keys(['stu1102', 'stu1104', 'stu1101', 'stu1103', 'stu1105'])
>>> "stu1101" in Dict.keys() #也可以判断字符串是否存在于字典所有keys所组成的列表中
True
#在Python2.7中

>>> a = {"a":"1","b":"2"}
>>> a.keys() #返回一个list类型
['a', 'b']
>>> list(a) #也返回一个list类型
['a', 'b']
>>> a.keys().index("b") #list类型才有index索引
1
>>> list(a).index("b") #list类型才有index索引
1 #在Python3中
>>> a = {"a":"1","b":"2"}
>>> list(a) #返回一个列表类型
['b', 'a']
>>> list(a).index("b") #列表类型才有索引
0
>>> a.keys() #返回的还是一个字典类型的keys
dict_keys(['b', 'a'])
>>> a.keys().index("b") #字典类型的keys没有索引
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'dict_keys' object has no attribute 'index'

2.6 提取字典里所有的values

#代码演示:

>>> Dict = {"stu1101":"Tom","stu1102":"Amy","stu1103":"feixue","stu1104":"zhangsan","stu1105":"lisi"}
>>> "Amy" in Dict #不能判断字符串是否存在于字典的values中
False
>>> Dict.values() #提取字典的所有values,返回一个字典类型的values列表
dict_values(['Amy', 'zhangsan', 'Tom', 'feixue', 'lisi'])
>>> "Amy" in Dict.values() #可以判断字符串是否存在于字典所有的values所组成的列表中
True

2.7 字典的合并

>>> Dict = {"stu1101":"Tom","stu1102":"Amy","stu1103":"feixue","stu1104":"zhangsan","stu1105":"lisi"}
>>> Dict2={"1":"2","3":"4","stu1102":"更新了"}
>>> Dict.update(Dict2)
>>> Dict
{'stu1105': 'lisi', 'stu1103': 'feixue', '3': '4', '1': '2', 'stu1104': 'zhangsan', 'stu1101': 'Tom', 'stu1102': '更新了'}

2.8 多级字典嵌套及操作

#代码演示:

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# author:Mr.chen av_catalog = {
"欧美":{
"www.youporn.com":["很多免费的,世界最大的","质量一般"],
"www.pornhub.com":["很多免费的,也很大","质量比yourporn高点"],
"x-art.com":["质量很高","全部收费,屌丝请绕过"]
},
"日韩":{
"tokyo-hot":["质量怎样不清楚,个人已经不喜欢日韩范了","听说是收费的"]
},
"大陆":{
"1024":["全部免费,真好,好人一生平安","服务器在国外,慢"]
}
} av_catalog["大陆"]["1024"][1] += ",可以用爬虫爬下来"
print (av_catalog["大陆"]["1024"]) #输出
[root@localhost scripts]# python3 test.py
['全部免费,真好,好人一生平安', '服务器在国外,慢,可以用爬虫爬下来']

2.9 循环dict

 #代码演示:

 #!/usr/bin/env python3
# -*- coding:utf-8 -*-
# author:Mr.chen Dict = {
"stu1001":"Tom",
"stu1002":"Amy",
"stu1003":"benet",
"stu1004":"yunjisuan"
} for key in Dict :
print (key,Dict[key]) #输出
[root@localhost scripts]# python3 test.py
stu1002 Amy
stu1001 Tom
stu1003 benet
stu1004 yunjisuan

2.10 循环dict时附带索引

#代码演示:

a = {
"yunjisuan":"33",
"benet":"44",
"Tom":"22",
"chensiqi":"88"
} for index,keys in enumerate(a) :
print (index+1,keys,a[keys]) #输出结果 [root@localhost scripts]# python3 test2.py
1 chensiqi 88
2 Tom 22
3 yunjisuan 33
4 benet 44

2.11 如何让字典有序?

#代码演示:

a = {
"yunjisuan":"33",
"benet":"44",
"Tom":"22",
"chensiqi":"88"
}
b = [] for index,keys in enumerate(a) :
b.append((index+1,keys,a[keys]))
print (index+1,keys,a[keys]) print (b) #输出结果 [root@localhost scripts]# python3 test2.py
1 Tom 22
2 yunjisuan 33
3 chensiqi 88
4 benet 44
[(1, 'Tom', '22'), (2, 'yunjisuan', '33'), (3, 'chensiqi', '88'), (4, 'benet', '44')]

三,利用字典优化"用户登陆接口程序"

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
# author:Mr.chen
#利用字典功能优化“用户登陆验证接口功能” users = {"chensiqi1":"666666","chensiqi2":"666666"}
error = [] while True :
user_Name = input("请输入登录用户的用户名:")
if user_Name in error :
print ("用户已经被锁定,请尝试登陆其他用户!")
elif user_Name in users.keys() :
for i in range(3) :
user_Passwd = input("请输入登陆用户名的密码:")
if user_Passwd == users[user_Name] :
print ("{}用户登陆成功!".format(user_Name))
exit()
else :
print ("用户账户或密码输入错误!请重新输入,您还有{}次机会。".format(2-i))
else :
print ("您的密码已经输错3次了,账户已经锁定!请尝试登陆其他用户。")
error.append(user_Name)
else :
print ("没有这个账户名,请重新输入!")

四,逻辑引导与作业

逻辑引导:

作业:

程序:三级菜单

要求:

  • [x] :打印省,市,县三级菜单
  • [x] :只能用一个字典来存取地区名称
  • [x] :可返回上一级
  • [x] :可随时退出程序
05-11 15:23
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