How can I read a column from excel while I do not want all the data of that column?

I want to plot four graphs in the same figure. I can read all of them from excel. But for first plotting i want to plot all the values of X; but the second plot I want to take the values after 5 intervals, the step size should be suppose 5, something like xmin:5: xmax. how i can do that?

X=readmatrix('phasesintegrated','Range','A2:A106'); 
Y1=readmatrix('phasesintegrated','Range','B2:B106');
Y2=readmatrix('phasesintegrated','Range','C2:C106');
plot(X,Y1,  'color','b','linewidth',2);
plot(X,Y2, 'Marker','o', 'color','b','linewidth',1);

Answer 1

[dpb]

It's VERY inefficient to open/read/close the same file three times, not to mention it just makes for more work to address multiple variables with sequentially-number names. The existence of such is a very good sign that MATLAB syntax isn't being used effectively.

Instead, do something more like

data=readmatrix('phasesintegrated');            % read the whole array at once
plot(data(:,1),data(:,2),'b-','linewidth',2);
hold on                                         % so can add to same axes
plot(data(:,1),data(:,3), 'bo-','linewidth',1);

Not sure what else, specifically you want to plot, but the "every fifth point" thing is trivial -- see <colon, :> for all the skinny on subscripting, but

nSkip=5;
plot(data(1:nSkip:end,1),data(1:nSkip:end,2),'rx');

would add the 2nd set of data with a red 'x' for every fifth point beginning with the first. You can change the starting index at will, too, of course.