python day1

一、python介绍：

1.官网：https://www.python.org/

2.发展历史：创始人为荷兰人吉多·范罗苏姆 ^[2]  （Guido van Rossum），脚本解释程序。

二、变量：存储接下来调用的东西。

变量定义的规则：只能是字母、数字、下划线的任意组合；数字不能开头；关键字不能声明为变量。

三、字符编码：

ASCII：美国标准信息交换码，最多可以给256个字符分配数值，即0~255，最多只能用8位来表示。

GB2312 ：支持汉字少，一般手机、MP3支持。

GBK：汉字扩展。

GB18030：汉字扩展，PC平台支持。收录少数民族文字。

编码方法时从上向下兼容。

Unicode：万国码。解决传统的字符编码的局限而产生。他为每种语言的每个字符设定了统一并且唯一的二进制编码。规定最少由16位来表示。

UTF-8：对Unicode的压缩和简化。将所有的字符和符号进行分类：ASCII中的用1个字节保存，欧洲字符用两个字节保存，东亚用3个保存。。。

## pycharm 默认用utf-8

四、用户交互

字符串拼接：

1.加号

name =input("name:")
age=input("age:")
job=input("job")
salary=input("salary:")
print(name,password)
info='''
------------info of'''+ name +'''-----------
Name:'''+name +'''
Age:'''+ age +'''
Job:'''+ job +'''
Salary:'''+ salary +'''
'''
print(info)

2.格式化字符串

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

注：从键盘输入的都是字符串类型数据

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

3.format格式化函数

name =input("name:")
age=input("age:")
print(type(age))
age=int(age)
print(type(age))
job=input("job")
salary=input("salary:")
print(name,password)
info='''
------------info of {_name}-----------
Name:{_name}
Age:{_age}
Job:{_job}
Salary:{_salary}
'''.format(_name=name,
           _age=age,
           _job=job,
           _salary=salary)
print(info)

name =input("name:")
age=input("age:")
print(type(age))
age=int(age)
print(type(age))
job=input("job")
salary=input("salary:")
print(name,password)
info='''
------------info of {0}-----------
Name:{0}
Age:{1}
Job:{2}
Salary:{3}
'''.format(name,age,job,salary)
print(info)

五、if else 流程判断

1.密文：

输入密码时，想用密文是导入模块getpass，getpass在pycharm中不好使

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

2.流程判断：

if elif else

_username="humiao"
_password="123456"
username = input("username:")
password=input("password:")
print(username,password)

if _username==username and _password==password:
    print("WELCOME user {name} login".format(name=username))
else:
    print("Invalid username or password")

 while

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

for

for i in range(10):
    print("loop",i)

for i in range(0,10,2):# 从0开始到10结束，2是步长就是隔一个挑一个，3，是隔两个跳一个
    print("loop",i)

continue：跳出本次，进行下次循环

for i in range(0,10):
    if i <3:
        print("loop",i)
    else:
        continue
    print("hehe")

break：直接跳出循环。

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

例：猜年龄

i.

age_of_oldboy=56
guess_age=int(input("guess age:"))
if guess_age==age_of_oldboy:
    print("yes,you got it")
elif guess_age> age_of_oldboy:
    print("think smaller")
else:
    print("think bigger")

ii.

猜三次年龄，三次内猜对，三次还猜不对就不再猜

##while true 版本
age_of_oldboy=56
count =0
while True:
    if count==3:
        break
    guess_age = int(input("guess age:"))
    if guess_age == age_of_oldboy:
        print("yes,you got it")
        break # 跳出循环
    elif guess_age > age_of_oldboy:
        print("think smaller")
    else:
        print("think bigger")
    count +=1

## while count版本
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 # 跳出循环
    elif guess_age > age_of_oldboy:
        print("think smaller")
    else:
        print("think bigger")
    count +=1
if count==3:
    print("you have tried too many times..fuck off")

##while else 版本
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 # 跳出循环
    elif guess_age > age_of_oldboy:
        print("think smaller")
    else:
        print("think bigger")
    count +=1
else:
    print("you have tried too many times..fuck off")

猜年龄for循环版：

1.猜三次就不能再猜

age_of_oldboy=56
for i in range(3):
    guess_age = int(input("guess age:"))
    if guess_age == age_of_oldboy:
        print("yes,you got it")
        break # 跳出循环
    elif guess_age > age_of_oldboy:
        print("think smaller")
    else:
        print("think bigger")
else:
    print("you have tried too many times..fuck off")z

##2.每猜三次是否还要再猜三次
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 # 跳出循环
    elif guess_age > age_of_oldboy:
        print("think smaller")
    else:
        print("think bigger")
    count +=1 #count=3的时候就已经猜了三次
    if count==3:
        continue_confiemation =input("Do you want to keep guessing?")
        if continue_confiemation !='n':
            count =0
else:
    print("you have tried too many times..fuck off")