I have a array of 61 number, i want to take mean of 1st and 17th number, then 2nd and 18th number and then want to put this mean values in a array?

I don't want to use loop here.

Answer 1

[KSSV]

A = rand(1,61) ; 
idx = [(1:46)' (16:61)'] ;   % get indices
iwant = mean(A(idx),2)

[Subhodh Sharma]

@KSSV thanks. What will be the method if we implement same analogy on a 3d matrix whose 3rd dimension is 61?

I am replacing the third dimension with the idx, but it's giving wrong answer.

I really appreciate your help!

[KSSV]

Tell me the dimensions of 3D matrix. What you expect from it.

[KSSV]

So you want mean of 1st and17th matrix, so you expect a 3D matrix of size 180*270..is it?

[Subhodh Sharma]

The final matrix will be a 3d matrix.

First layer (or matrix) of 3d output= mean of 1st and 17 th matrix of original 3d data

Second layer of 3d output=mean of 2nd and 18th matrix of original 3d data

....so on. Hope this clarifies more.

[KSSV]

So output will be of size 180*1*3d..

[KSSV]

A = rand(180,270,61) ; 
idx = [(1:46)' (16:61)'] ;
B = zeros(180,270,46,2) ; 
B(:,:,:,1) = A(:,:,idx(:,1)) ; 
B(:,:,:,2) = A(:,:,idx(:,2)) ; 

Check and then use....confirm the result with a loop.

[Subhodh Sharma]

@kssv thanks for your help, but this not what I was looking for. I solved it.

Thanks man!