Can I put markers on only some of the points in my plot?

I refer to the following Solution: http://www.mathworks.com/support/solutions/en/data/1-18Q90/?solution=1-18Q90

It was mentioned that "the request for a built-in MATLAB command to do this automatically has been forwarded to our development staff for consideration for a future version of MATLAB."

Is this feature available now in the latest Matlab?

Answer 1

[Daniel Shub]

To my knowledge it has not happened yet. The work round seems pretty good to me.

figure;
XVec = 0:(pi/2):10*pi;
YVec = sin(XVec);
plot(XVec, YVec);
hold on;
plot(XVec(1:4:end), YVec(1:4:end), '+');

figure;
XVec = 0:(pi/16):10*pi;
YVec = sin(XVec);
plot(XVec, YVec);
hold on;
plot(XVec(1:8:end), YVec(1:8:end), '+');

notice the second plot is just '+' and not '-+'.

[Henry]

Sorry, but the work round in that link is awful to me.

> plot(XVec,YVec)

> plot(XVec(1:4:end),YVec(1:4:end), '+')

Since 'plot' just draws a line between two adjacent points in the data array, the above two plots are different and may *not* overlap. Just imagine XVec and YVec is a sin function evaluated at 0, pi/2, pi, 3*pi/2, 2*pi, ... Then the second plot will just give a flat horizontal line.

[Daniel Shub]

Have you tried it (see my edit). The first plot, plots a "line" which linearly interpolates between the data points in (XVec, YVec). This line will go through all the data points in (XVec, Yvec). The second plot will not plot a line. It will just plot symbols on every 4th point in (XVec, Yvec)

[Henry]

Thanks Daniel. Somehow you code segment showed up only 2 minutes ago, though I saw the first sentence in your answer right after it was posted.

[Daniel Shub]

Nope, I edited in repose to your comment. You cannot put formatted code in comments (which is a real pain).

Answer 2

[Henry]

hmm, got a solution. When calling 'plot' for the second time, use 'LineStyle', 'none'.

[Daniel Shub]

Try the second plot with '+' and not '-+'