Use Double Array Values to Label Plot

I have a variable 'xx' that is a 1x9 double. I want to use those values to label the points along the line in plot(t,xx)

This is my code

Ts = 1/8; 
t = 0:Ts:1;

x = @(t) cos(2*pi*t-(pi/2));

xx = x(t);

labels = {'Sample 1', 'Sample 2', 'Sample 3', 'Sample 4', 'Sample 5', 'Sample 6', 'Sample 7', 'Sample 8', 'Sample 9'};
plot(t,xx,'rd-', 'linewidth', 1.5, 'MarkerSize', 9, 'MarkerFaceColor', 'w'), grid on
text(t,xx,labels)

[cdawg]

Would making labels = string(xx) work?

Ts = 1/8; 
t = 0:Ts:1;
x = @(t) cos(2*pi*t-(pi/2));
xx = x(t);
labels = string(xx);
plot(t,xx,'rd-', 'linewidth', 1.5, 'MarkerSize', 9, 'MarkerFaceColor', 'w'), grid on
text(t,xx,labels)

[collegestudent]

But I also need to label each point with the correct sample number

Answer 1

[dpb]

"Would making labels = string(xx) work?"

Did you try?

It works for a basic definition of what "working" might mean; you might find something like

text(t,xx,compose('%0.3f',xx))

more pleasing to the eye. Investigate the named parameters to text regarding position the text so as to not write on top of the data itself...

[cdawg]

@dpb is right, it does look much better. If you want to include the sample number in there as well, try something like this

Ts = 1/8; 
t = 0:Ts:1;
x = @(t) cos(2*pi*t-(pi/2));
xx = x(t);

for ii = 1:length(xx)
    label{ii} = sprintf('Sample %d: %0.3f', ii, xx(ii));
end
figure();
plot(t,xx,'rd-', 'linewidth', 1.5, 'MarkerSize', 9, 'MarkerFaceColor', 'w'), grid on
text(t,xx,label)

I'm sure there's an easier way to do it without a for loop...

And again dpb is right- as you can see the positioning of the labels doesn't look very good. You'll have to mess around with the location of the labels (or add the Sample label and the data label separately..)

[dpb]

Try something more like

Ts = 1/8; 
t = 0:Ts:1;
xx = cos(2*pi*t-(pi/2));        % no need for the anonymous function here...

plot(t,xx,'rd-', 'linewidth', 1.5, 'MarkerSize', 9, 'MarkerFaceColor', 'w'), grid on
ylim(1.2*ylim)
hold on
labels=compose('Sample: %d\n%0.3f',[1:numel(xx)].',xx.');
hT=text(t+0.025,xx+0.05,labels);
hT(end).HorizontalAlignment='right';
hT(end).Position=[1-0.025 0.1];

for starters. One can always be more clever about trying to locate where place annotations based on actual data and anything known a priori about shape of curve, etc., to minimize occluding data more than necessary.

The fixup here for the last position to place it to the left instead of the right owing to knowing it will run off the RH side otherwise, is one obvious nicety.