Python学习 Week1

1 #在屏幕中打印出Hello World!
2 print("Hello World!")

#定义一个变量，将Hello World!赋值给它，打印出来
a="Hello World!"
print(a)

#使用input函数获取用户输入的Hello World！赋值到变量a中
a=input("please input Hello World!:")
print (a)

#字符串拼接，用户输入任意字符，直接生成Hello （str）！
#方法一
a=input ("please input your name:")
print ("Hello",a,"!")

#方法二
a= input ("please input your name:")
info=‘‘‘Hello %s‘‘‘%(a)+"!"
print (info)

#方法三
a= input ("please input your name:")
info=‘‘‘Hello {b}‘‘‘.format(b=a)+"!"
print (info)

#用户输入用户名和密码，密码要求不显示，使用getpass模块
import getpass
username=input("Please input username:")
password=getpass.getpass("Please input password:")
print ("username:",username,"password:",password)

#if 条件:
#   执行语句
#else :
#   执行语句
a=int(input("Please input a number:"))
if a<3:
   print("Y")
else:
   print("N")

#if 条件:
#   执行语句
#elif :
#   执行语句
#else :
#   执行语句
a=int(input("Please input a number:"))
if a<3:
   print("a<3")
elif a>3:
   print("a>3")
else :
   print("a=3")

#判断用户输入的账号和密码是否正确
import getpass
username="kiwi"
password="kiwi123"
_username=input("Plsease input username:")
_password=getpass.getpass("Please input password:")
if username==_username and password==_password :
   print("Welcome",_username)
else :
   print("Worng Username or Password,please input again!")

#定义一个变量count，条件为一直为真就循环执行命令
#while True:
#    执行命令
count=0
while count=0:
    print ("a is apple;b is ball!")
#定义一个变量count，如果小于3，打印a is apple，反之打印b is ball
#while True:
#    执行命令
#else :
#    执行命令
count=0
while count<3:
    print ("a is apple")
    count+=1
else :
   print("b is ball")
   count+=1
#定义一个变量count，打印10次a is apple
#while True
#   执行条件
#  if 等于10次
#      break
count=0
while count>=0:
    print ("a is apple;")
    count+=1
    if count==10:
     break

#判断用户输入的账号和密码是否正确,如果输入错误3次，自动退出
import getpass
username="kiwi"
password="kiwi123"
count=0
while count>3 :
    _username=input("Plsease input username:")
    _password=getpass.getpass("Please input password:")
   if username==_username and password==_password :
         print("Welcome",_username)
         break
   elif count==2:
         print("So many worngs,please try again!")
         break
   else:
         print("Worng Username or Password,please input again!")
         count += 1

#循环10次
for i in range(10):
    print("loop:",i)
#循环10次，如果i小于5，不打印
for i in range(10):
    if i<5:
        continue
    print("loop:",i)
#循环10次，如果i大于5，自动退出
for i in range(10):
    if i>5:
        break
    print("loop:",i)

import getpass
username="kiwi"
password="kiwi123"
for i in range(3):
   _username=input("Plsease input username:")
   _password=getpass.getpass("Please input password:")
   if username==_username and password==_password :
         print("Welcome",_username)
         break
   elif i==2:
         print("So many worngs,please try again!")
         break
   else:
         print("Worng Username or Password,please input again!")