【Python全栈笔记】07 [模块二] 20 Oct 冒泡排序

给出一个列表，进行冒泡排序

原理算法：

 li = [52, 37, 23, 11, 3, 1, ]

 print(li)

 # 每次循环，进行一次排序，列表内数字两两比较，最大的数字排到最末尾
 # 一共循环len(li) - 1 次

 for i in range(len(li) - 1):
     if li[i] > li[i + 1]:
         temp = li[i]
         li[i] = li[i+1]
         li[i + 1] = temp
 print(li)

 for i in range(len(li) - 2):
     if li[i] > li[i + 1]:
         temp = li[i]
         li[i] = li[i+1]
         li[i + 1] = temp
 print(li)

 for i in range(len(li) - 3):
     if li[i] > li[i + 1]:
         temp = li[i]
         li[i] = li[i+1]
         li[i + 1] = temp
 print(li)

 for i in range(len(li) - 4):
     if li[i] > li[i + 1]:
         temp = li[i]
         li[i] = li[i+1]
         li[i + 1] = temp
 print(li)

 for i in range(len(li) - 5):
     if li[i] > li[i + 1]:
         temp = li[i]
         li[i] = li[i+1]
         li[i + 1] = temp
 print(li)

 '''
 输出的结果：
 [52, 37, 23, 11, 3, 1]
 [37, 23, 11, 3, 1, 52]
 [23, 11, 3, 1, 37, 52]
 [11, 3, 1, 23, 37, 52]
 [3, 1, 11, 23, 37, 52]
 [1, 3, 11, 23, 37, 52]
 '''

可以看到以上排序每次步骤一致，只有一个变量（即不用对比最后一个元素）

因此，可以再设置一个变量j, 作为循环时候的变量简化操作，由此得到：

 li = [52, 37, 23, 11, 3, 1, ]
 print(li)

 for j in range(1, len(li)):
     for i in range(len(li) - j):
         if li[i] > li[i + 1]:
             temp = li[i]
             li[i] = li[i+1]
             li[i + 1] = temp
     print(li)
 '''
 结果：
 [52, 37, 23, 11, 3, 1]
 [37, 23, 11, 3, 1, 52]
 [23, 11, 3, 1, 37, 52]
 [11, 3, 1, 23, 37, 52]
 [3, 1, 11, 23, 37, 52]
 [1, 3, 11, 23, 37, 52]
 '''