新手Python学习记录Day1

声明：学习视频来源：https://www.bilibili.com/video/av17118368/?p=15
学习资料来源：http://www.cnblogs.com/alex3714/articles/5465198.html

输入输出

输入

name = input("name:")
age =int(input("age:"))
print(type(age), type(str(age)))
job = input("job:")
#input默认输入的都是字符串，因此需要强制转换age类型

格式化输出方法

方法一：利用占位符

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

方法二：重新命名，记住是花括号{}

info2 = '''
-------info2 of {name_} ------
Name:{name_}
Age:{age_}
Job:{job_}
'''.format(name_=name,
          age_=age,
          job_=job)
print(info2)

方法三：不用命名，但需要按顺序format，也是花括号{}

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

输入密码时利用密文

'''标准库——是不用下载，直接导入即可的包'''
import getpass
_username = "first"
_password = "123"
username = input("username:")
password = getpass.getpass("password:")

if _username==username and _password==password:
    print("Wecome user {name} login...".format(name=username))
else:#if 和 else 两者同级
    print("Invalid user!")
print(username,password)
#IndentationError:表示缩进出错

循环语句

while 循环语句

count = 0
while count<3:
    print("count:",count)
    count +=1
else:
    print("you have tried too many times")#else 可以与while 的判断相呼应

for循环语句

for i in range(10):
#for i in range(0,10,3):  //表示步长
    print("loop:",i)
    if i<5:
        continue
        print("...")
    print("0.0")

for i in range(10):
    print("------",i)
    for j in range(10):
        print(j)
        if j >5:
            break #break 结束最近的循环

if, elif, else 语句

age_of_oldboy = 56
count = 0
while True:
    if count==3:
        break
    guess_age = int(input("guess age:"))#input默认输入的都是字符串，所以需要强制转换
    if guess_age ==age_of_oldboy:
        print("yes,you got it.")
        break
    elif guess_age>age_of_oldboy:
        print("think smller...")
    else:
        print("think bigger...")
    count +=1

age_of_oldboy = 56
count = 0
while count<3:
    guess_age = int(input("guess age:"))#input默认输入的都是字符串，所以需要强制转换
    if guess_age ==age_of_oldboy:
        print("yes,you got it.")
        break
    elif guess_age>age_of_oldboy:
        print("think smller...")
    else:
        print("think bigger...")
    count +=1
    if count == 3:
        countine_confirm = input("do you want to keep guessing...?")
        if countine_confirm != "n":
            count =0
else:
    print("Too many times")

作业

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

import getpass
_username = "first"
_password = "123"
for i in range(3):
    username = input("username:")
    password = getpass.getpass("password:")
    if _username==username and _password==password:
        print("Wecome user {name} login...".format(name=username))
        break
    else:#if 和 else 两者同级
        print("Invalid user!")
        continue
else:
    print("Your account is locked, you cannot try again!")

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