Python 二维列表平均列

Question

I have a 2d list of the format peaks = [[3.56, 7.94, 3.56,... ], [...]] .

I'm trying to use the following list comprehension to create a list containing the averages of each of the columns of peaks . That looks like this,

[sum(peaks[:,i])/len(peaks) for i in range(len(peaks[0]))]

As far as I know, this is proper column-slicing and list comprehension syntax, and yet I get this error:

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

Can someone help me out?

Answer 1

First you can transform the row to column in your list, for example:

[[1,2,3],[4,5,6]] to [(1, 4), (2, 5), (3, 6)]

Then you can use statistics.mean()

>>>import statistics
>>>l=[]
>>>peaks = [[1,2,3],[4,5,6]]
>>>peak=[*zip(*peaks)]
>>>peak
[(1, 4), (2, 5), (3, 6)]
>>>for i in peak:
>>>    l.append(statistics.mean(i))
>>>l
[2.5, 3.5, 4.5]