学习总结：
变量，字符的由来，python2和python3的区别，控制语句：if，for，while，break，continue用法
学习示例：
if用法1：判断年龄
# -*- coding: utf-8 -*-
# Author:Yang Hang
age = 75
guess_age = input("请输入年龄：")
guess_age = int(guess_age)
if guess_age == age:
print("你猜对了！")
elif guese_age > age:
print("请往小的猜！")
else:
print("请往大的猜！")
if用法2：登陆示例
# -*- coding: utf-8 -*-
# Author:Yang Hang
_username = 'yanghang'
_passwd = '
username = input("username:")
passwd = input("password:")
if username == _username and passwd == _passwd:
print("成功登陆！")
else:
print("用户名或密码有误，请重新输入！")
for用法1：输出1到10
# -*- coding: utf-8 -*-
# Author:Yang Hang
for i in range(10):
print("loop",i)
for用法2：猜年龄
# -*- coding: utf-8 -*-
# Author:Yang Hang
age = 75
count = 0
for i in range(3):
guess_age = int(input("请输入年龄："))
if guess_age == age:
print("恭喜你猜对了！")
break
elif guess_age > age:
print("请往小的猜！")
else:
print("请往大的猜！")
else:
print("输入次数超过三次，结束")
while用法1：
# -*- coding: utf-8 -*-
# Author:Yang Hang
count = 0
while count < 100:
print("count:",count)
count = count +1
while用法2：
# -*- coding: utf-8 -*-
# Author:Yang Hang
age = 75
count = 0
'''
#版本1:
while True:
if count == 3:
print("输入次数超过三次，结束")
break
guess_age = int(input("请输入年龄："))
if guess_age == age:
print("恭喜你猜对了！")
break
elif guess_age > age:
print("请往小的猜！")
else:
print("请往大的猜！")
count += 1
'''
#优化版本
while count <3:
guess_age = int(input("请输入年龄："))
if guess_age == age:
print("恭喜你猜对了！")
break
elif guess_age > age:
print("请往小的猜！")
else:
print("请往大的猜！")
count +=1
if count == 3:
countine_confirm =input("你还想继续猜吗..?")
if countine_confirm != 'n':
count = 0
else:
print("输入次数超过三次，结束")