python - TypeError：列表索引必须是整数或切片，而不是浮点数；

Question

我有一个错误的问题：

TypeError: list indices must be integers or slices, not float

在下面我的代码的这一行：

a1[j+1] = key

下面是我的代码：

a1 = [4.3, 5.2, 5.0, 1.5, 3.8, 4.1, 5.5, 1.9]
sum = 0
count = len(a1)
for i in a1:
    sum = sum + float(i)
    key = a1[index]
    j = i-1
    while j >= 0 and key < j : 
        a1[j + 1] = a1[j] 
        j -= 1
    a1[j+1] = key 
mean = sum/count
print("Answer for y = 1.5")
print("Average: {0}".format(mean))

我想要一个插入排序来对数组 a1 进行排序

Answer 1

对于插入排序，你可以试试这个。但是，使用您的方法找出总数将导致错误的 ans，因为 a1 在每次迭代中都会被修改，并且会导致总数的计算不正确。相反，您可以使用python 提供的sum()方法来计算列表的总数。

a1 = [4.3, 5.2, 5.0, 1.5, 3.8, 4.1, 5.5, 1.9]
total = 0
count = len(a1)
for i in range(1, len(a1)):
    key = a1[i] 
    j = i-1
    while j >=0 and key < a1[j] : 
        a1[j+1] = a1[j] 
        j -= 1
    a1[j+1] = key

total =sum(a1)
mean = total/count
print("Answer for y = 1.5")
print("Average: {0}".format(mean))
print(a1)

输出 ：

Answer for y = 1.5
Average: 3.9124999999999996
[1.5, 1.9, 3.8, 4.1, 4.3, 5.0, 5.2, 5.5]