how to range data and find maximum value for each range by using loop

I have data (AB) consisting of two columns. The number of rows of this data is 80315. I want to divide this number into (1: 2000: 80315) and take the maximum values for each period (based on the second column, also i want to index the firt colum).

I using this code but its very long.

a = AB([1:2000],:);

aa=max(a);

a1 = AB([2000:4000],:);

aa1=max(a1);

a11 = AB([4000:6000],:);

aa11=max(a11);

maxvalues=([aa;aa1;aa11])

[Pooja Kumari]

According to your code, you want to get maximum value for each period, what do you mean by second column?

[abdullah al-dulaimi]

i mean the output will be 2 coluoms not 1

Answer 1

[Pooja Kumari]

Dear abdullah al-dulaimi,

It is my understanding that you are facing issues with huge vector and instead of hardcoding, you want a generalized form of code for taking the maximum value for your data for each period by taking 2000 data at a time out of 80315 rows of data.

Please find below an example code for the same with random dataset of 80315 rows and 2 columns:

data = rand(80315,2); %data 
index = 1;
for i = 1:1999:80315-1999
    array_data = data(i:i+1999,:);  %data is divided into %2000 samples at a time. 
    output(index,1) = max(array_data(:)); %taking max of all values in a period
    index = index +1;
end

For more information on array indexing, you can refer to the below link:

https://in.mathworks.com/help/matlab/learn_matlab/array-indexing.html

Sincerely,

Pooja Kumari

[abdullah al-dulaimi]

dear Pooja Kumari ,

Thank you for your kind efforts.

best regard