If……else 基本结构：
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If condition: do something else: do something |
或者
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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.")
原文：http://www.cnblogs.com/lk-b/p/5904494.html