pytthon基础第一天——if判断、while循环、for循环、python字符串

user_lisa = 18   # 定义一个年龄
count = 0  # 循环次数
while count < 3:  # 循环的次数小于3次
    user = input(‘please your enter username:‘).strip()  # 用户输入,去两边空格
    if user.isdigit():  # 如果输入的是数字字符串的情况下
        user = int(user)  # 转换成整型
        if user == user_lisa:  # 用户输入的值和定义的值相等时,退出整个程序
            print(‘you got it‘)  
            exit()  
        elif user > user_lisa:  # 用户输入的值大于定义的值,提示输小点
            print(‘try smaller‘)  
        else:
            user < user_lisa   # 用户输入的值小于定义的值,提示输大点
            print(‘try bigger‘)
    else:
        print(‘try again‘)   # 如果用户输入的不是数字,提示重试
    count += 1   # 循环的次数自加1
print(‘too many times‘) # 提示次数太多

count = 0
user_name = ‘lisa‘
pwd = ‘123‘
while count <3:
    username =input(‘please enter your username:‘)
    password =input(‘please enter your password:‘)
    if username == user_name and password == pwd:
        while True:
            user_cmd = input(‘Please enter your cmd:‘).strip()
            print(‘The cmd is %s‘%user_cmd)
            if user_cmd == ‘q‘:
                break
        break
    else:
        print(‘login failed‘)
    count += 1

count = 0
user_name = ‘lisa‘
pwd = ‘123‘
while count <3:
    username =input(‘please enter your username:‘)
    password =input(‘please enter your password:‘)
    if username == user_name and password == pwd:
        while True:
            user_cmd = input(‘Please enter your cmd:‘).strip()
            print(‘The cmd is %s‘%user_cmd)
            if user_cmd == ‘q‘:
                exit()
    else:
        print(‘login failed‘)
    count += 1

# 使用while循环输出1、2、3、4、5、6、8、9、10
count = 1       # 定义初始值
while count < 11:  # 当count小于11时，执行以下代码
    if count == 7:  # 当count等于7时，count自加1，且退本次循环
        count += 1
        continue
    print(count) # 打印count的值
    count += 1 # count自加1