Python 基础之三条件判断与循环

Posted 2020-08-10

If……else 基本结构：

If condition: do something else: do something

或者

If condition: do something elif condition: do something else: do something

 

Python 通过缩进来确定一段代码的作用域，同一级别的代码缩进要保持一致，官方建议是4个空格。

提示：IndentationError，都为代码中存在缩进错误。

小练习：

# 猜luck number,n=6

# 猜的数字比6大，提示小一点

# 猜的数字比6小，提示大一点

#猜的数字等于6，提示Bingo

代码：

 

 1 #!user/bin/env python3
 2 # -*- coding: gbk -*-
 3 luck_num = 19
 4 input_num = int(input("please input the luck num:"))
 5 if input_num == 19:
 6     print("Bingo!")
 7 elif input_num > luck_num:
 8     print("the num is Bigger!")
 9 else:
10     print("the num is smaller")

 

 

 

 

 

引入循环while，加入次数限制，代码：

 

 1 #!user/bin/env python3
 2 # -*- coding: gbk -*-
 3 luck_num = 19
 4 input_num = int(input("please input the luck num:"))
 5 if input_num == 19:
 6     print("Bingo!")
 7 elif input_num > luck_num:
 8     print("the num is Bigger!")
 9 else:
10     print("the num is smaller")

 

 

 

For 循环方式：

 1 for num_of_times in range(3):
 2     # When failure exit after three times.
 3     input_num = int(input("please input the luck num:"))
 4     if input_num == 19:
 5         print("Bingo!")
 6         break
 7     elif input_num > luck_num:
 8         print("the num is Bigger!")
 9     else:
10         print("the num is smaller")
11 else:
12     print("you try too many times.")