Python：TypeError：'NoneType' 对象没有属性 '__getitem__'
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Python: TypeError: 'NoneType' object has no attribute '__getitem__'
提问by user3578070
When I was trying to run this:
当我试图运行这个时：
lista=[4,10,4,15,6,15,18,10,7]
listb=[5,10,5,18,11,35,21,10,7]
import math
for i in range(9):
a=math.log10(lista[i])
b=math.log10(listb[i])
lista=lista.insert(i,a)
listb=listb.insert(i,b)
for i in range(17,8,-1):
lista.remove(lista[i])
listb.remove(listb[i])
print(lista)
print(listb)
Then I got :
然后我得到：
File "C:/Python27/Lib/site-packages/xy/untitled3.py", line 11, in <module>
a=math.log10(lista[i])
TypeError: 'NoneType' object has no attribute '__getitem__'
I need help. Thank you very much
我需要帮助。非常感谢
采纳答案by sshashank124
This is because insert()doesn't return anythingand so you are assigning Noneto your lists in the following lines:
这是因为insert()不返回任何内容，因此您None在以下几行中分配给您的列表：
lista=lista.insert(i,a)
listb=listb.insert(i,b)
Just doing the following is enough:
只需执行以下操作就足够了：
lista.insert(i,a)
listb.insert(i,b)
Examples
例子
a = [1,2,3]
b = a.insert(1,1)
>>> print b
None
>>> print a
[1,1,2,3]
回答by Martijn Pieters
lista.insert()returns Nonebecause the list is altered in-place, and does notreturn the updated list.
lista.insert()返回None因为列表改变就地，一点不返回更新列表。
During the second iteration of the loop then listais Noneand lista[i]fails.
在循环的第二次迭代，然后lista是None和lista[i]失败。
Don't assign the result of the insertion:
不要分配插入的结果：
for i in range(9):
a=math.log10(lista[i])
b=math.log10(listb[i])
lista.insert(i,a)
listb.insert(i,b)
With that correction, your code prints:
通过该更正，您的代码将打印：
[0.6020599913279624, 0.6020599913279624, 0.6020599913279624, 0.6020599913279624, 0.6020599913279624, 0.6020599913279624, 0.6020599913279624, 0.6020599913279624, 0.6020599913279624]
[0.6989700043360189, 0.6989700043360189, 0.6989700043360189, 0.6989700043360189, 0.6989700043360189, 0.6989700043360189, 0.6989700043360189, 0.6989700043360189, 0.6989700043360189]
