Python函数(续)

先学习之前未完成的冒泡算法

li = [13,22,6,99,11]

从小到大

从第一个数字比较把大的往后移位

for m in range(4):

　　num1 = li[m]

　　num2 = li[m+1]

　　if num1 > num2:

　　　　temp = li[m]

　　　　li[m] = num2

　　　　li[m+1] = temp

print li

循环四次就把最大数放到列表的最后

for m in range(3):

　　num1 = li[m]

　　num2 = li[m+1]

　　if num1 > num2:

　　　　temp = li[m]

　　　　li[m] = num2

　　　　li[m+1] = temp

以此类推写成以下代码

vim day4-1.py

#!/usr/bin/python
# -*- coding:utf-8 -*-

li = [13,22,6,99,11]
for m in range(4):		#循环
	num1 = li[m]
	num2 = li[m+1]
	if num1 > num2:		#前一个数字和后一个对比如果前面数字大与后面的对调
		temp = num1
		li[m] = num2
		li[m+1] = temp
print li

for m in range(3):
        num1 = li[m]
        num2 = li[m+1]
        if num1 > num2:
                temp = num1
                li[m] = num2
                li[m+1] = temp

print li

for m in range(2):
        num1 = li[m]
        num2 = li[m+1]
        if num1 > num2:
                temp = num1
                li[m] = num2
                li[m+1] = temp

print li

for m in range(1):
        num1 = li[m]
        num2 = li[m+1]
        if num1 > num2:
                temp = num1
                li[m] = num2
                li[m+1] = temp

print li			#多次循环得到排序结果

[[email protected] scripts]# python day4-1.py
[13, 6, 22, 11, 99]
[6, 13, 11, 22, 99]
[6, 11, 13, 22, 99]
[6, 11, 13, 22, 99]

这样的循环很繁琐,假如不知道列表的长度更加麻烦需要多次循环

vim day4-2.py

#!/usr/bin/python
# -*- coding:utf-8 -*-
li = [13,22,6,99,11]
for n in range(1,len(li)-1):            #外层循环1,2,3,4
        for m in range(len(li)-n):      #内层循环4,3,2,1
                num1 = li[m]
                num2 = li[m+1]
                if num1 > num2:
                        temp = li[m]
                        li[m] = li[m+1]
                        li[m+1] = temp
print li

　　运行结果的一样的

[[email protected] scripts]# python day4-2.py
[6, 11, 13, 22, 99]