How to extract data from on a timetable dependent on a date range

Question

Tomas Miguieles 2020-7-8

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/561431-how-to-extract-data-from-on-a-timetable-dependent-on-a-date-range

编辑： Walter Roberson 2020-7-17

I have an 81033×4 table in which the first column holds the timestamp for each date and time (format mm/dd/yy HH:mm), the second column is the datenum for each timestamp, and the other 2 columns are the recordings for each stamp

How do I extract sets of data from my table depending on the timestamp? I'd like to extract the rows for each year of data (2010:2020)
How do I plot timestamp vs data (Acc_Ext, Acc_Int) for each year?

The data looks like this:

(disregard the x34, I can create one that with only the first 4 columns)

An initial idea I had is:

[num,text] = xlsread('NODE2.WDH.csv', 'A1:D81034');
    datenumColumn = num(:,1);
    rowtotal = length(datenumColumn);
    
    % Find datenum value for start of each year
        for n = 2010:2021
        Y(n) = datenum(n,1,1);
        end
        
    ind = find(Y > 0);
    A = [ind',Y(ind)'];
    B = A(:,2); % B is the array containing all the date strings for the start of each year
    
    data_2010 = num((B(1)<=datenumColumn)&(datenumColumn<=B(2)), :);
    data_2011 = num((B(2)<=datenumColumn)&(datenumColumn<=B(3)), :);
    data_2012 = num((B(3)<=datenumColumn)&(datenumColumn<=B(4)), :);
    data_2013 = num((B(4)<=datenumColumn)&(datenumColumn<=B(5)), :);
    data_2014 = num((B(5)<=datenumColumn)&(datenumColumn<=B(6)), :);
    data_2015 = num((B(6)<=datenumColumn)&(datenumColumn<=B(7)), :);
    data_2016 = num((B(7)<=datenumColumn)&(datenumColumn<=B(8)), :);
    data_2017 = num((B(8)<=datenumColumn)&(datenumColumn<=B(9)), :);
    data_2018 = num((B(9)<=datenumColumn)&(datenumColumn<=B(10)), :);
    data_2019 = num((B(10)<=datenumColumn)&(datenumColumn<=B(11)), :);
    data_2020 = num((B(11)<=datenumColumn)&(datenumColumn<=B(12)), :);
    
    % Create Figure for all data from Node
    t = tiledlayout(3,4,'TileSpacing','Compact','Padding','Compact');
    % Tiles
    for i = 0:12
        nexttile()
        x = data_201i(:,1);
        y1 = data_201i(:,2);
        y2 = data_201i(:,3);
        plot(x,y1,'k-');
        title('2020')
        hold on;
        plot(x,y2,'b-');
        datetick('x','mmm','keepticks') % This function read the time intervals and displays them in the x-axis
        tstart = data_201i(1,1);
        tend = data_201i(size(data_201i,1),1);
        xlim([tstart tend])
        xlabel('Month')
    end

However, I can't get the data to be plotted for each iteration.

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Answer 1

Walter Roberson 2020-7-8

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/561431-how-to-extract-data-from-on-a-timetable-dependent-on-a-date-range#answer_462716

编辑：Walter Roberson 2020-7-17

在 MATLAB Online 中打开

https://www.mathworks.com/help/matlab/ref/timerange.html

However, I would suggest that you might not be asking the best question. I would suggest that you instead consider

G = findgroups(year(YourTable.Timestamp));
hold on
workfun = @(ts, Ext, Int) plot(ts, Ext, ts, Int, 'DisplayName', string(year(ts(1))));
plot_handles = splitapply( workfun, YourTable.Timestamp, YourTable.Acc_NBSP2Ext, YourTable.Acc_NBSP2Int, G);

You might want to do the work function slightly differently to be able to distinguish the line for internal and external.

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Tomas Miguieles 2020-7-8

Thanks for your answer. That code helps me segregate all the data by years, but how can I get a figure of multiple plots for each year? Or one plot at a time with its corresponding legend and axis labels (which in this case are the same for all plots).

Walter Roberson 2020-7-17

You can make workfun into whatever it needs to be. Have it accept one parameter for each variable it will need for the plotting. List all of those same variables in order after the function handle in the splitapply() call. The function handle you pass to splitapply can be the handle to a "real" function instead of an anonymous function.

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