python 学习之路 Day1

python 基础

1.第一个python程序

print("Hello World")

2.变量

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']

变量的赋值

name="name"
_name="name"

3.字符编码

#_*_coding:utf-8_*_

4.字符编码的区别与介绍

当行注视：# 被注释内容

多行注释：""" 被注释内容 """

name = input("name:")
#raw_input 2.x   input 3.x
#input 2.x =
age = int(input("age:") ) #integer
print(type(age)   , type(  str(age) ))
job = input("job:")
salary  = input("salary:")

info = '''
-------- info of  %s  -----
Name:%s
Age:%d
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)

5.用户交互程序

#!/usr/bin/env python
#_*_coding:utf-8_*_
#name = raw_input("What is your name?") #only on python 2.x

name = input("What is your name?")
print("Hello " + name )

输入密码时，如果想要不可见，需要利用getpass 模块中的 getpass方法，即：

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import getpass
# 将用户输入的内容赋值给 name 变量
pwd = getpass.getpass("请输入密码：")
# 打印输入的内容
print(pwd)

6.if else流程判断

age_of_oldboy =56

if guess_age == age_of_oldboy :
    print("yes, you got it. ")
    break
elif guess_age > age_of_oldboy:
    print("think smaller...")
else:
    print("think bigger!")

7.while 循环

age_of_oldboy = 56
count = 0
while count <3:
    guess_age = int(input("guess age:") )
    if guess_age == age_of_oldboy :
        print("yes, you got it. ")
        break
    elif guess_age > age_of_oldboy:
        print("think smaller...")
    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("you have tried too many times..fuck off")

8.for 循环

for i in range(10):
    print('----------',i)
    for j in range(10):
        print(j)
        if j >5:
            break

9.作业，登录判断输入用户名和密码认证成功显示欢迎登录输错三次锁定

#!/usr/bin/env python
#-*- coding:utf-8 -*-

import getpass
import sys

count = 0
filePath = "test.txt"

while count < 3:
    userName = input("input you username:")
    #passWord=getpass.getpass("input you password:")
    passWord = input("input you password:")
    file = open(filePath, "r")
    for line in file:
        if line.strip() == userName:
            print("This username is lock")
            sys.exit()
    file.close()
    if userName == "test" and passWord == "123456":
        print("Welcome login system!")
        break
    else:
        print("username or password is wrong")
    count += 1
else:
    file = open(filePath, "a+")
    file.write(userName)
    file.write("\n")
    file.close()
    print("check your username and password...")