study note1

1.变量名要有含义，要用英文单词，不能用-，因为是减号，第一个字符不能是数字。

大写变量名默认为常量，但是也可以改。（潜规则）

不要用中文...虽然python居然支持中文变量名，也不要用拼音。

2.关于字节：在UTF-8中存一个英文字符占用1个字节，存一个中文字符占用3个字节。

3.python2与3版本的区别：由于在python2的版本中并不是utf8的默认字体，需要在解释器中加入# -*- coding: utf-8 -*-，然后就可以识别中文了；在python2中raw_input等于python3中的input。

4.格式化输出：

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# __author__ = "Deakin"
# Email: 469792427@qq.com
# Date: 2017/12/22

name=input("Name:")
age=int(input("Age:"))
print(type(age))
job=input("Job:")
salary=input("Salary:")
info='''
----------info of %s----------

Name:%s
Age:%d   #这里是数字格式，age定义的时候加了int强制转换
Job:%s
Salary:%s
''' %(name,name,age,job,salary)
print(info)

OR-------------------------------------------------------

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# __author__ = "Deakin"
# Email: 469792427@qq.com
# Date: 2017/12/22

name=input("Name:")
age=input("Age:")
job=input("Job:")
salary=input("Salary:")

info2='''

-----------info2 of {0}-----------
Name:{0}
Age:{1}
Job:{2}
Salary:{3}
'''.format(name,age,job,salary)

OR---------------------------------------------------

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# __author__ = "Deakin"
# Email: 469792427@qq.com
# Date: 2017/12/22

name=input("Name:")
age=input("Age:")
job=input("Job:")
salary=input("Salary:")

info3='''

-----------info3 of {djname}-----------
Name:{djname}
Age:{djage}
Job:{djjob}
Salary:{djsalary}
'''.format(djname=name,djage=age,djjob=job,djsalary=salary)

print(info3)

5.将明文密码改成密文
首先宣告import getpass（在pycharm中无法测试，请到windows命令提示符中尝试）

EG:
import getpass
username=input("username:")
password=getpass.getpass("password:")
print(username,password)

c:\Users\Deakin\PycharmProjects\untitled2\11.22>python passwd.py
username:Deakin
password:
Deakin 123456

6.if else逻辑判断

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# __author__ = "Deakin"
# Email: 469792427@qq.com
# Date: 2017/12/22

djusername="Deakin"
djpassword="pocket123"
username=input("username:")
password=input("password:")

print(username,password)

if djusername==username and djpassword==password:
    print("welcome to login {name}'s account".format(name=username))
else:
    print("invalid username or password")

C:\Users\Deakin\PycharmProjects\untitled2\venv\Scripts\python.exe C:/Users/Deakin/PycharmProjects/untitled2/11.22/passwd.py
username:Deakin
password:pocket123
Deakin pocket123
welcome to login Deakin's account

Process finished with exit code 0

 

 ---------------------------------------

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# __author__ = "Deakin"
# Email: master@liwenzhou.com
# Date: 2017/12/22

age_of_deakin=18
guess_age=int(input("guess_age:")) #input中输出的默认为string字符串格式，所以在进行比较大小的时候需要强制转换成int
if age_of_deakin>guess_age:
    print("too small")
elif age_of_deakin<guess_age:
    print("too big")
else:
    print("pretty good,you are right!")



7.while循环

count=0
while True:
    print("count:",count)
    count=count+1  #count +=1


----------------------------------------------

#! /usr/bin/env python
# -*- coding: utf-8 -*-
# __author__ = "Deakin"
# Email: master@liwenzhou.com
# Date: 2017/12/22
count=0
age_of_deakin=18
while True:
    if count==3: #或者while count <3:
        break
    guess_age=int(input("guess_age:"))

    if age_of_deakin>guess_age:
        print("too small")
    elif age_of_deakin<guess_age:
        print("too big")
    else:
        print("pretty good,you are right!")
        break
    count=count+1
else:
    print("you have try too many times,fuke off!")