MATLAB Answers

Trying to set Y-Axis to Minutes:Seconds for swim times. Would like to set range from 0 to 3:30 and eliminate leading zeros

5 views (last 30 days)
Maria Baeza
Maria Baeza on 11 Jul 2021
Commented: Maria Baeza on 13 Jul 2021
%Group4_Statistics are datenums
boxplot(Group4_Statistics,'Labels',{'IM_100','Free_50', 'Breast_50','Back_50', 'Fly_50'});
title('2021 Times by Stroke', FontName = 'Arial', FontSize = 12, FontWeight = 'Bold');
ylabel('Time');
datetick('y',"MM:SS");

Accepted Answer

Cris LaPierre
Cris LaPierre on 13 Jul 2021
Edited: Cris LaPierre on 13 Jul 2021
Boxplot (and boxchart) do not yet support datetimes (see here), so you need to work with numeric values (like datenums), as you are doing already. ytickformat will not work. To display ylabels in "m:ss" format, you will need to manually create a string array containing your labels and manually update the ylabels.
I elected to convert your datenums to minutes, as I found it easier to work with 0-3.5 instead of 738157.0000000000 - 738157.0024305555.
I also notice these plots automatically scale the y axis, so you need to explicitly set the limits you want to have. Finally, only datetimes support a "m:ss" format, so I elected to create a vector of datetimes, set the format, and convert to string to create the ylabels.
load Swimming-Group4.mat
% convert data to times
tms = timeofday(datetime(Group4_Statistics,'ConvertFrom',"datenum"));
% plot using time converted to decimal minutes.
boxplot(minutes(tms),'Labels',{'IM_100','Free_50', 'Breast_50','Back_50', 'Fly_50'});
% set the y axis ticks and limits. Values represent time in minutes
yticks(0:0.5:3.5)
ylim([0 3.5]) % without this, the 0 and 3.5 ticks are not visible.
% create ylabels in m:ss format
yticklabels(string(datetime(2021,1,1,0,0,0,'Format',"m:ss")+minutes(0:0.5:3.5)))
I noticed you are only interested in the times. I'm curious how you collected your data to include a date as well. I suspect these times were not collected on Jan 1, 2021 at midnight. To help make the yaxis values meaningful, I stripped away the date info using the timeofday function. I suspect that my code looks more complicated because I'm also formatting the data to what I want it to be. However, if the data were just time (durations, or time measured in seconds or decimal minutes) some of this would not be necessary. For more, see the Represent Dates and Times in MATLAB page.
  2 Comments

Sign in to comment.

More Answers (2)

Akira Agata
Akira Agata on 12 Jul 2021
Edited: Akira Agata on 12 Jul 2021
How about the following solution?
% Sample data
t = 0.25+3*rand(100,1);
% Create boxplot
figure
boxplot(t)
d = 0:0.5:3.5;
ax = gca;
ax.YLim = [0 3.5];
ax.YTick = d;
ax.YTickLabel = compose('%d:%02d',floor(d)',mod(d*60,60)');
ylabel('Time','FontSize',12);
  1 Comment
Maria Baeza
Maria Baeza on 12 Jul 2021
Thank you for your quick response. When I input the suggested changes (below), the Y Axis show timing information as I would like but the boxplot no longer appears? The information is type: datenum as should be in in the range of 30 seconds to 3 minutes.. which I think the label now shows but maybe that is hours?
Any suggestions would be greatly welcomed.
boxplot(Group4_Statistics,'Labels',{'IM_100','Free_50', 'Breast_50','Back_50', 'Fly_50'});
title('2021 Times by Stroke', FontName = 'Arial', FontSize = 12, FontWeight = 'Bold');
ylabel('Time');
datetick('y',"MM:SS");
d = 0:0.5:3.5;
ax = gca;
ax.YLim = [0 3.5];
ax.YTick = d;
ax.YTickLabel = compose('%d:%02d',floor(d)',mod(d*60,60)');
subtitle('Age: 11-12',FontName = 'Arial', FontSize = 10, FontWeight = 'Bold');

Sign in to comment.


Cris LaPierre
Cris LaPierre on 12 Jul 2021
Your format spec is forcing two digits for the minutes ('MM:SS'). The way to eliminate a leading zero is to only use one 'M'. However, it doesn't look like datetick supports that (see dateFormat inputs here).
The solution may be to use ytickformat instead. It supports single-digit minute formats (see here).
ytickformat('m:ss')
  7 Comments

Sign in to comment.

Products


Release

R2021a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by