# Finding an average of sample point in an array with irregular intervals

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Pavel Kutsenko on 22 Jan 2019
Commented: Pavel Kutsenko on 23 Jan 2019
Hi!
I would like to take an average of sample windows in my data.
(I1 = [1:10])
For regular intervals i could use the
Av1 = mean(I1([1:2:10;2:2:10]))
However, i am currently facing a problem where a gap between windows increases every time by 1 unit. Sort of like that:
Av2=mean(I2([1:(1:4):10;2:(1:4):10]))
How can i do it in Matlab?

Image Analyst on 22 Jan 2019
Have you tried a nested for loop? Try it.
Pavel Kutsenko on 22 Jan 2019
sorry, i have no idea how to implement this

Omer Yasin Birey on 23 Jan 2019
Edited: Omer Yasin Birey on 23 Jan 2019
Hi Pavel, you may try this
Av2 = cell(4,4);
% I2 = rand(20,20,20);
for i = 1:4
for j = 1:4
Av2{i,j}=mean([I2(1:i:10),I2(2:j:10)]);
end
end
meanWind = mean(cellfun(@(c) c, Av2(:)));

Pavel Kutsenko on 23 Jan 2019
no error, byt Av2 is a matrix 4x4 and meanWind is only one number. is there a way of getting answer as an array, of four numbers (in this case)? Av2=[2,3,5,8]
sorry to bother
Omer Yasin Birey on 23 Jan 2019
Of course, it is possible. You are changing the columns here so I assumed you want to calculate the mean of columns. You can use the code below for mean of columns. Else if you want to take mean of rows use the second code.
Av2 = zeros(4,4);
% I2 = rand(20,20,20);
for i = 1:4
for j = 1:4
Av2(i,j)=mean([I2(1:i:10),I2(2:j:10)]);
end
end
meanOfEachColumns = mean(Av2',2);
if you want the mean of rows
Av2 = zeros(4,4);
% I2 = rand(20,20,20);
for i = 1:4
for j = 1:4
Av2(i,j)=mean([I2(1:i:10),I2(2:j:10)]);
end
end
meanOfEachColumns = mean(Av2,2);
Pavel Kutsenko on 23 Jan 2019
But i dont really have rows or columns, i just have an array of numbers. So if I use this code with I2=[1:10] i get (5.6, 5.3, 5.6, 5.4) as my means and i am looking for (2,3,5,8)