Taking Mean Of Specific Rows and Columns Within A Loop

Hello, I have a data matrix of 288000 x 5 and I would like to compute the mean of column 2 in increments of 1200.

Therefore, I want to take the mean from 1:1200 and put it in slot 1 of a new vector. Then take 1201:2400 and put it in slot 2 of the new vector.

I have attempted it and was successful doing it outside of a loop but now that I attempt a loop I am having trouble.

y = 1;

for x = 1 : 1200: x < 288000

Mean(y) = mean(Data([x:(x+1199)],2);

y = y + 1;

end

It works for the first data point when I format it outside a loop like:

Mean(1) = mean(Data([1:1200]),2);

Mean(2) = mean(Data([1201:2400]),2);

and so on...

Thank you!

Answer 1

[Richard Brown]

You don't need a loop. Basic idea:

• extract column 2.
• Reshape it into a matrix with columns 1200 tall
• take the mean of each column

The following code will work (so long as you have a number of rows that is a multiple of 1200)

means = mean(reshape(Data(:, 2), 1200, size(Data, 1)/1200))

[Daniel Koziel]

Thank you my friend! I also found it to work inside a loop using:

y = 1;

for x = 1: 1200 : 287999

Min(1,y) = min(Data((x:x+1199),2)); %Calculating Min

Max(1,y) = max(Data((x:x+1199),2)); %Calculating Max

Mean(1,y) = mean(Data((x:x+1199),2)); %Calculating Mean

Var(1,y) = var(Data((x:x+1199),2)); %Calculating Var

y = y + 1;

end