MATLAB: How to count the number of points in a scatter plot

Hi,

I made a scatter plot using two columns where there were a few NaNs. Those rows were automatically get eliminated when I use the "scatter" command. Now I want to see how many data points on the scatter plot. Please help me with this. Thanks

Best Answer

How about using isnan() on the x and y to find out which are not nans?

numberOfGoodPoints = sum(~isnan(x) & ~isnan(y))

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MATLAB: How to find peaks for a graph plotted in semi-log axes and to extract the values of peak and FWHM

Use findpeaks with more than 2 outputs:

[pks,locs,widths,proms] = findpeaks(PeakSig,x);

See the documentation section on Peak Prominences (link) for details. It specifically describes the ‘widths’ output as ‘Display the prominences and the widths at half prominence of all the peaks.’

MATLAB: Counting data points

If you have the "c" as an integer or logical array, and if you have the Image Processing Toolbox, you can do it in one line with regionprops(). Just simply say "measurements = regionprops(~c, 'Area')" Here's a full demo:

% Create sample data.
c = [0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0]
% Measure the zero sections - KEY LINE OF CODE RIGHT HERE!
measurements = regionprops(~c, 'Area')
% Display results.
fprintf('The number of zero sections is %d.\n', length(measurements));
fprintf('The sizes of zero sections are:\n');
allAreas = [measurements.Area]

Best Answer

Related Solutions

MATLAB: How to find peaks for a graph plotted in semi-log axes and to extract the values of peak and FWHM

MATLAB: Counting data points

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