CODEWITHSUNDEEP
pythonnumpy
Aalok Parkash
Aalok Parkash

Reputation: 51

How do I change taking the mean based on the length of the list? (Python)

I have a list containing lists containing arrays, something like this:

A = [
    [
        array([[ 1.,  4.3, 0.,  0.],
               [ 0.,  0.,  0.,  0.],
               [ 0.,  0.,  0.,  0.],
               [ 0.,  0.,  0.,  0.]])
    ],

    [
        array([[ 5.,  0.,  0.,  0.],
               [ 0.,  0.,  0.,  0.],
               [ 0.,  0.,  0.,  0.],
               [ 0.,  0.,  0.,  0.]])
    ]
]

So I basically have two 4x4 matrices inside of this thing. Now, the goal is to take the average of these two which I managed to do with:

np.mean([A[0][0],A[1][0]],axis=0)

I also have another matrix B which consists of three 4x4 matrices, and the average would then be something like

np.mean([B[0][0],B[1][0]],B[2][0],axis=0)

I want to generalize this so that I dont have to rewrite the np.mean part each time. So I would probably use the length of A (2) or length of B (3) to construct that, but I'm not sure how to get something like

np.mean(C[0][0],C[1][0],[...][0],[n-1][0],axis=0)

where n is len(C).

How can I implement this? Thanks!

Upvotes: 3

Views: 73

Answers (1)

tobias_k
tobias_k

Reputation: 82929

You could just use a list comprehension:

>>> np.mean([A[i][0] for i in range(len(A))], axis=0)

Or shorter, more readable and "pythonic":

>>> np.mean([a[0] for a in A], axis=0)
array([[ 3.  ,  2.15,  0.  ,  0.  ],
       [ 0.  ,  0.  ,  0.  ,  0.  ],
       [ 0.  ,  0.  ,  0.  ,  0.  ],
       [ 0.  ,  0.  ,  0.  ,  0.  ]])

Upvotes: 1

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