Add a datestr to duration data to get in datestr format

Hi, I have a graph where Im plotting on the x-axis time by using tic then in a loop making measurements 'Y' and performing tend=toc

I dor ecord the actual date / time at the start too.

 dt = datestr(now,'dd-mmm-yyyy HH-MM-SS');   %get current dateTime

Once my loop has finished an I have a plot of all the Y's against their time of measurements (starting at 0), how can I add the "duration" onto the actual datestr, so I can have on the x-axis the actual date time.

thanks

Jason

Answer 1

[Steven Lord]

Rather than using date strings or serial date numbers, use datetime arrays.

x = 1:10;
dt = datetime(2025, 12, x);
y = x.^2;
plot(dt, y, 'o-')

●

If you're adding points to something like an animatedline iteratively, that works too.

figure
h = animatedline(dt(1), y(1), LineStyle = '-', Marker = 'o');
for k = 2:numel(y)
    addpoints(h, dt(k), y(k));
end

[Jason]

Thankyou

Answer 2

[Walter Roberson]

Answering the question as given

NOW = datetime('now');
%here accumulate array of tic/toc values into variable DURATIONS.
%...
dt = datestr(NOW + DURATIONS / (24*60*60), 'dd-mmm-yyyy HH-MM-SS');

However, chances are high that you do not want to plot all DURATIONS values. You probably want something more like

NOW = datetime('now');
%here accumulate array of tic/toc values into variable DURATIONS.
%...
dt = NOW + DURATIONS / (24*60*60);
plot(dt, VALUES);
datetick('x', 'dd-mmm-yyyy HH-MM-SS')

That said... working with datetime() values is typically much nicer.

[Jason]

Thanks Walter