Set the startdate and enddate of x axis using plot

This is the plot i have done. I would like to set the 0 value of x axis to 2019 12 26 and 71 value of x axis to 2019 12 30. The values within is not needed. There is 71 data points for y axis.

Answer 1

[Walter Roberson]

linspace works with datetime objects. datetime(year, month, day)

Answer 2

[Ameer Hamza]

By default, MATLAB creates a numeric ruler for XAxis. There is no direct way to convert numeric ruler to a datetime ruler. The only way is to create a new figure, format the axis, and copy the axis to the first axes object. The following shows an example by creating a temporary invisible figure.

Create an example figure with numeric ruler at x-axis

f1 = figure();
ax1 = axes();
t = 5:0.1:30;
p1 = plot(t, sin(t));

Create an invisible figure with datetime ruler

%% now create an invisible axes with datetime ruler as X-Axis
dates = datetime('2019 12 26', 'InputFormat', 'yyyy MM dd'):datetime('2019 12 30', 'InputFormat', 'yyyy MM dd');
f2 = figure('Visible', 'off');
ax2 = axes();
plot(dates,0);
ax2.XAxis.TickValues = dates;

Copy the ruler from invisible figure to the original figure

%% adjust the axis limits of 1st axes and assign the ruler from second axes to first
p1.XData = (p1.XData - p1.XData(1))/(p1.XData(end) - p1.XData(1))*(numel(dates)-1);
ax1.XAxis = ax2.XAxis;

%% delete the invisible figure
delete(f2);

[Walter Roberson]

This can be done as shown, but it is much easier to just to plot with datetime objects in the first place.

You do not need to construct a new figure to get to a DatetimeRuler:

dt_ruler = matlab.graphics.axis.decorator.DatetimeRuler;

Now here set dt_ruler Limits, TickValues, TickLabelFormat. Then

p1.XRuler = dt_ruler;

[Ameer Hamza]

Thanks. The code is simpler by directly assigning the datetime ruler. For OP's reference, here is the code using method suggested by Walter

f1 = figure();
ax1 = axes();
t = 5:0.1:30;
p1 = plot(t, sin(t));

%%
ax1.XRuler = matlab.graphics.axis.decorator.DatetimeRuler;
drawnow;

dates = linspace(datetime('2019 12 26', 'InputFormat', 'yyyy MM dd'), datetime('2019 12 30', 'InputFormat', 'yyyy MM dd'), numel(t));
p1.XData = dates;
dates2 = datetime('2019 12 26', 'InputFormat', 'yyyy MM dd'):datetime('2019 12 30', 'InputFormat', 'yyyy MM dd');
ax1.XAxis.TickValues = dates2;