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How to find the most frequently repeated time interval?

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Matlab warrior! In the data travels, there is a column with start and end time. Each interval has certain value or zero. I have to find the most repeated time (hot spot) among those travels which is not equal to zero. For ex, among two, 1st interval "06:30"-"07:30", and second "06:00 - 07:00", then hotspot would be "06:30-07:00". I have tried smth like:
load_dumb = zeros(24*60+1,1);
for i = 1:length(end_timedumb)
[~, ~, ~, H, MN, ~] = datevec(st_timesumb(i));
T_Stdumb = H*60+MN+1;
[~, ~, ~, H, MN, ~] = datevec(end_timedumb(i));
T_Enddumb = H*60+MN+1;
if isnan(T_Enddumb)
minscale_DCH1(T_Stdumb:T_Enddumb,1) = minscale(T_Stdumb:T_Enddumb,1) + 1;
load_dumb(T_Stdumb:T_Enddumb,1) = load_dumb(T_Stdumb:T_Enddumb,1) + dumb_chargingpower(i);
TimeM = 1:length(minscale);
TimeH = TimeM/60;
but that gives me only the overall peak that values accumulated among intervals. However, I need to find specific interval that is the most common.


Asrorkhuja Ortikov
Asrorkhuja Ortikov on 18 Sep 2020
Hey, thanks for the thread. I just did, there are several time durations, it's up to you which one to choose.

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Accepted Answer

Turlough Hughes
Turlough Hughes on 18 Sep 2020
First I read in data as a string array
opts = detectImportOptions(filename,'TextType','string');
opts.SelectedVariableNames = {'Var2','Var3'}; % alternatively {'Var4','Var5'}, or {'Var6','Var7'}
D = readmatrix(filename,opts);
Convert each string to a duration in terms of minutes from 00:00
D = minutes(duration(D,'InputFormat','hh:mm'));
D(D(:,2)==0,2)=1440; % set 00:00 in the second column to 1440 minutes
To find the hotspot, I create a logical array, M, which has the same number of rows as D, and 1440 columns (one for each minute of the day). Values are set to true if they fall within the range:
M = false(size(D,1),24*60);
for c = 1:size(D,1)
You can then sum up each column to find the frequency with which a given minute appeared in the time intervals.
figure(), plot(duration(0,0,0):minutes(1):duration(23,59,0),sum(M))
One thing to note, if the range from your data begins and ends on the same minute then that minute is included using the code as it is.


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Asrorkhuja Ortikov
Asrorkhuja Ortikov on 19 Sep 2020
No, i don't want to exclude rows containing 00:00, I mean for each duration there is a value that contains charging power. Which means if I want to include that third column, value changes. For example, in duration from 06:00 to 06:30 charging power can be zero. In that case, I don't want that duration to be counted as occurance.
Four highest hotspot that maximises the sum of occurances, correct.
Turlough Hughes
Turlough Hughes on 20 Sep 2020
No values in column J were zero, did you mean column I? That would be done as follows:
opts.SelectedVariableNames = {'Var9'}; % column I in excel
isOff = readmatrix(filename,opts)==0; % rows equal to 0
D(isOff,:) = []; % delete rows corresponding to a 0 in I.
As for finding the four hotspots which maximise occurrences, it is a little more involved, i suggest opening a new question on it.
Asrorkhuja Ortikov
Asrorkhuja Ortikov on 23 Sep 2020
@Turlough Hughes, thank you. I will make another question, you made my life much easier )

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