day1-python-基本语法

一、hello world程序

#!/usr/bin/env python
print("Hello World!")

二、变量

#!/usr/bin/env python
name = "hhh"
name2 = name
print("My name is",name,name2)

name = "ggg"
print(name,name2)

上述代码声明了变量名name，变量name的值为“hhh”

变量定义的规则：

• 变量名只能是 字母、数字或下划线的任意组合
• 变量名的第一个字符不能是数字
• 以下关键字不能声明为变量名
  ['and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'exec', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'not', 'or', 'pass', 'print', 'raise', 'return', 'try', 'while', 'with', 'yield']三、字符编码

三、字符编码

python解释器在加载 .py 文件中的代码时，会对内容进行编码（默认ascill）
ASCII（American Standard Code for Information Interchange，美国标准信息交换代码）是基于拉丁字母的一套电脑编码系统，主要用于显示现代英语和其他西欧语言，其最多只能用 8 位来表示（一个字节），即：2**8 = 256-1，所以，ASCII码最多只能表示 255 个符号。
显然ASCII码无法将世界上的各种文字和符号全部表示，所以，就需要新出一种可以代表所有字符和符号的编码，即：Unicode
Unicode（统一码、万国码、单一码）是一种在计算机上使用的字符编码。Unicode 是为了解决传统的字符编码方案的局限而产生的，它为每种语言中的每个字符设定了统一并且唯一的二进制编码，规定虽有的字符和符号最少由 16 位来表示（2个字节），即：2 **16 = 65536，
注：此处说的的是最少2个字节，可能更多
UTF-8，是对Unicode编码的压缩和优化，他不再使用最少使用2个字节，而是将所有的字符和符号进行分类：ascii码中的内容用1个字节保存、欧洲的字符用2个字节保存，东亚的字符用3个字节保存...

#!/usr/bin/env python
# -*- coding:utf-8 -*-
name = "你好，世界"
print(name)

四、用户输入

#!/usr/bin/env python
# -*- coding:utf-8 -*-
name = input("name:")
age = input("age:")
job = input("job:")
salary = input("salary:")

info = '''
-----------  info of %s  ------------
Name:%s
Age:%s
Job:%s
Salary:%s
''' % (name,name,age,job,salary)

info2 = '''
-----------  info of {_name}  ------------
Name:{_name}
Age:{_age}
Job:{_job}
Salary:{_salary}
'''.format(_name=name,
           _age=age,
           _job=job,
           _salary=salary)

info3 = '''
-----------  info of {0}  ------------
Name:{0}
Age:{1}
Job:{2}
Salary:{3}
'''.format(name,age,job,salary)
print(info3)

五、表达式if...else

场景一：用户登陆验证

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import getpass
_username = 'hhh'
_password = '123'
username = input("username:")
# password = getpass.getpass("password:")
password = input("password:")
if _username == username and _password == password:
    print("Welcome user {name} login...".format(name=username))
else:
    print("Invalid username or password!")

场景二：猜年龄

#!/usr/bin/env python
# -*- coding:utf-8 -*-
my_age = 28
guess_age = int(input("input your guess num:"))
if guess_age == my_age:
    print("Congretulations,you got it!")
elif guess_age < my_age:
    print("Oops,think bigger!")
else:
    print("think smaller!")

六、表达式while循环

#!/usr/bin/env python
# -*- coding:utf-8 -*-
count = 0
while True:
    print("count:",count)
    count = count +1
    if ount == 1000:
        break

优化猜年龄：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
my_age = 28
count = 0
while count <3:
    guess_age = int(input("input your guess num:"))
    if guess_age == my_age:
        print("Congretulations,you got it!")
        break
    elif guess_age < my_age:
        print("Oops,think bigger!")
    else:
        print("think smaller!")
    count +=1
else:
    print("you have tried too many times...fuck off")

七、表达式for循环

#!/usr/bin/env python
# -*- coding:utf-8 -*-
for i in range(0,10,1):
    print("loop",i)

优化猜年龄：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
my_age = 28
for i in range(3):
    guess_age = int(input("input your guess num:"))
    if guess_age == my_age:
        print("Congretulations,you got it!")
        break
    elif guess_age < my_age:
        print("Oops,think bigger!")
    else:
        print("think smaller!")
else:
    print("you have tried too many times...fuck off")

无限次猜年龄：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
my_age = 28
count = 0
while count <3:
    guess_age = int(input("input your guess num:"))
    if guess_age == my_age:
        print("Congretulations,you got it!")
        break
    elif guess_age < my_age:
        print("Oops,think bigger!")
    else:
        print("think smaller!")
    count +=1
    if count ==3:
        countine_confirm = input("do you want to keep guessing..?")
        if countine_confirm != 'n':
            count = 0
else:
    print("you have tried too many times...fuck off")

八、表达式continue

#!/usr/bin/env python
# -*- coding:utf-8 -*-
for i in range(0,10):
    if i<3:
        print("loop",i)
    else:
        continue
    print("hehe...")

九、循环套循环

#!/usr/bin/env python
# -*- coding:utf-8 -*-
for i in range(10):
    print("--------------",i)
    for j in range(10):
        print(j)
        if j>5:
            break

十、作业

作业二：编写登陆接口

• 输入用户名密码
• 认证成功后显示欢迎信息
• 输错三次后锁定

#!/usr/bin/env python
# -*- coding:utf-8 -*-
message_list = open("message.txt").readlines()
locked_list = open("locked.txt").readlines()
d = {}

for i in range(len(message_list)):
    d[message_list[i].split(' ')[0]]=message_list[i].split(' ')[1]

count = 0
while count<3:
    username = input("username:")
    password = input("password:")
    if username in locked_list:
        print("Your username is locked! ")
        break
    else:
        if int(d[username]) == int(password):
            print("Welcome user {name} login...".format(name=username))
            break
        else:
            print("Invalid username or password!")
        count +=1
        if count ==3:
            open("locked.txt",'w').write(username)

作业三：多级菜单

• 三级菜单
• 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 -*-
data = {"福建":
            {"漳州":{"南靖":["龙山","小山城"],"平和":{},"龙海":{}},
            "福州":{"鼓楼":{},"台江":{},"晋安":{}},
            "厦门":{"思明":{},"湖里":{},"海沧":{}}
            },
        "广东":
            {"广州":{"越秀":{},"天河":{},"海珠":{}},
            "深圳":{"罗湖":{},"福田":{},"南山":{}},
            "东莞":{"罗湖":{},"福田":{},"南山":{}}
             },
        "四川":
            {"成都":{"青羊":{},"金牛":{},"武侯":{}},
            "绵阳":{"游仙":{},"安州":{},"江油":{}},
            "宜宾":{"南溪":{},"江安":{},"长宁":{}}
             },
        }
exit_flag = False

while not exit_flag:
    for i in data:
        print(i)
    choice = input("选择进入1>>:")
    if choice in data:
        while not exit_flag:
            for i2 in data[choice]:
                print(i2)
            choice2 = input("选择进入2>>:")
            if choice2 in data[choice]:
                while not exit_flag:
                    for i3 in data[choice][choice2]:
                        print(i3)
                    choice3 = input("选择进入3>>:")
                    if choice3 in data[choice][choice2]:
                        for i4 in data[choice][choice2][choice3]:
                            print(i4)
                        choice4 = input("最后一层，按b返回>>:")
                        if choice4 == "b":
                            pass
                        elif choice4 == "q":
                            exit_flag = True
                    if choice3 == "b":
                        break
                    elif choice3== "q":
                        exit_flag =True
            if choice2 == "b":
                break
            elif choice2 == "q":
                exit_flag = True