入门一：python变量、获取值、标准输出、循环判断语句

　　变量是由字母、数字和下划线组成的，数字不能作为开头。

　　python中没有常量，一般用常量的时候将变量名大写就可以了，注意后面不要修改它的值。

　　变量命令：使用下划线分隔。

　　字符编码在代码开头加入一行

1 # -*- coding:utf-8 -*-

获取输入的值input：

　　普通输入：

1 name = input("name:")
2 age = int(input("age:"))
3 job = input("job:")
4 salary = input("salary:")

　　密文输如：

1 import getpass
2
3 password = getpass.getpass("password:")

标准输出的几种方式：

　　第一种：

 1 info2 = ‘‘‘
 2 -------------info of {_name}---------
 3 Name:{_name}
 4 Age:{_age}
 5 Job:{_job}
 6 Salary:{_salary}
 7 ‘‘‘.format(_name=name,
 8            _age=age,
 9            _job=job,
10            _salary=salary)

　　第二种：

1 info = ‘‘‘
2 --------------------info 0f %s---------------
3 Name:%s
4 Age:%d
5 Job:%s
6 Salary:%s
7 ‘‘‘%(name,name,age,job,salary)

if-else循环

　　猜年龄：

1 age_of_oldboy = 56
2
3 guess_age = int(input("guess age:"))
4 if guess_age>age_of_oldboy:
5     print("your guess is older.")
6 elif guess_age==age_of_oldboy:
7     print("you are right!")
8 else:
9     print("your guess is younger.")

while循环

　　在猜年龄的基础上控制只让猜三次：

 1 while count<3:
 2     guess_age = int(input("guess age:"))
 3     if guess_age>age_of_oldboy:
 4         print("your guess is older.")
 5     elif guess_age==age_of_oldboy:
 6         print("you are right!")
 7         break
 8     else:
 9         print("your guess is younger.")
10
11     count = count + 1
12     print("you have {_count} times.".format(_count=3-count))
13 #if count == 3:
14 else:
15     print("sorry,you try too many times")

for循环：

##基础格式1 for i in range(1,10,2):
2     print("loop ",i)

　　用for循环写猜密码：

 1 age_of_oldboy = 56
 2
 3 for i in range(3):
 4     guess_age = int(input("guess age:"))
 5     if guess_age>age_of_oldboy:
 6         print("your guess is older.")
 7     elif guess_age==age_of_oldboy:
 8         print("you are right!")
 9         break
10     else:
11         print("your guess is younger.")
12
13     print("you have {_count} times.".format(_count=2-i))
14 #if count == 3:
15 else:
16     print("fuck")