Python 基础之三条件判断与循环

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：

 

#!user/bin/env python3
# -*- coding: gbk -*-
luck_num = 19
input_num = int(input("please input the luck num:"))
if input_num == 19:
    print("Bingo!")
elif input_num > luck_num:
    print("the num is Bigger!")
else:
    print("the num is smaller")

 引入循环while，加入次数限制，代码：

#!user/bin/env python3
# -*- coding: gbk -*-
luck_num = 19
input_num = int(input("please input the luck num:"))
if input_num == 19:
    print("Bingo!")
elif input_num > luck_num:
    print("the num is Bigger!")
else:
    print("the num is smaller")

 For 循环方式：

for num_of_times in range(3):
    # When failure exit after three times.
    input_num = int(input("please input the luck num:"))
    if input_num == 19:
        print("Bingo!")
        break
    elif input_num > luck_num:
        print("the num is Bigger!")
    else:
        print("the num is smaller")
else:
    print("you try too many times.")

 continue，跳过

 break，中断

for i in range(10):
    if i < 5:
        continue
    print(i)

#result
5
6
7
8
9

 continue 和 break的区别

 continue 是跳过当前循环块的剩余语句，进行下一次循环。break 是跳出当前循环块，停止当前循环。