MATLAB: Filtering values from a curve

filfiltering values

I have a curve x vs. y and I'm reading into Matlab through excel (xlsread).
I want to filer some values off. I want to filter the y (and corresponding x of course) which are greater than a ceratin value (1500).
How can I achieve this please?
Please help…I shall be grateful

Best Answer

  • Sounds like you want to remove y-values greater than a certain value.
    One way:
    idx = find(y>1500);
    % now remove the y values and the corresponding x-values
    y(idx) = [];
    x(idx) = [];
    Note that if your x-values were originally evenly-spaced, the above will alter that spacing. Not sure if that is important. There are other things you can do that will preserve the equal spacing. For example, you can set y-values greater than 1500 to NaN (not a number)
    y(y>1500) = NaN;