trying to find highest values in a time segment

I have a excel sheet (size 950x8) from which i need to find highest/lowest values in time period (first column which is date) and one of the other columns . Let's say 'which 7 days had the highest values'. I think i need to do this through loop somehow, but not really sure how.

Any help would be appreciated.

Answer 1

[Image Analyst]

Use maxk

%data = readmatrix(filename);
%values = data(:, 3); % For example data you want to check is in column 3.
values = rand(1, 10) % Sample data

values = 1×10

0.9677 0.7763 0.9682 0.5586 0.7599 0.0597 0.7981 0.0562 0.6211 0.0802

[maxValues, indexesOfMaxes] = maxk(values, 7)

maxValues = 1×7

0.9682 0.9677 0.7981 0.7763 0.7599 0.6211 0.5586

indexesOfMaxes = 1×7

3 1 7 2 5 9 4

%maxDates = data(indexesOfMaxes, 1); % Get corresponding dates from column 1

Answer 2

[Peter Perkins]

It's not clear to me that Image Analyst's solution answers your question, mostly because your question is not very clear. If the question is, "what are the seven days that individually had the seven largest values?", then that seems like one solution. If you have dates and values, you are better off reading into a timetable and then just sorting by the variable of interest, but either would work.

But if the question is, "which seven day period had the largest values?", then you should create a timetable and use retime to aggregate to weeks, using something like @max as your aggregation method.

[Dominik]

Image analyst's answer was, lest's say good enough. I'm new to matlab and it's usually enough for me to see how to start, I can get it somehow to work after that. So yeah, i'm thankful for any advice. Also thanks for that ''which seven day period had the largest values" , I was wondering how to do it (didn't need it in this case but hey good to know).