MATLAB: How to delete columns of a matrix containing specific values in bottom row

columnsdeletematrixmodification

Hi. I am working on a program that generates a 2xN matrix that looks something like this

ModRows = [7 11 21 27 243 2817 3114 3489;...
           2  2  4  6  13  279   1   150]

What I want to do is search the matrix for values in the second row that are below 2 and delete the respective column, so I would get something like this, for example:

ModRows = [21 27 243 2817 3489;...
           4   6  13  279  150;]

I have no idea where to start. I can't use an index i from 1 to the size of ModRows, because whenever I delete a column, ModRows becomes shorter, resulting in an error.

Any help would be much appreciated!

Marc

Best Answer

Test this:

    is_exclude = ModRows(end,:) < 2;
    ModRows( :, is_exclude ) = [];

or did you mean "<= 2"?

And search for "Using Logicals inArray Indexing" in the help

Related Solutions

MATLAB: How to delete an entire column if any 1 element in that column is above a threshold

A is your matrix.

A(:,max(A)>1.2)=[];

MATLAB: Creating a matrix with alternating and increasing values

I was able to figure it out:

x_coor = zeros(17,75);
delta_x = 0.2; %cm
for i=1:17
    if mod(i,2) == 0
        x_coor(i,2) = delta_x/2;
    else
        x_coor(i,2) = 0;
    end
end
for j=1:17
    if mod(j,2) == 0
        x_coor(j,3) = 0;
    else
        x_coor(j,3) = delta_x;
    end
end
for col=4:75
    if mod(col,2) == 0
        for row=1:17
            if mod(row,2) == 0
                x_coor(row,col) = x_coor(row,col-2) + delta_x;
            end
        end
    elseif mod(col,2) ~= 0
        for row1 = 1:17
            if mod(row1,2) ~= 0
                x_coor(row1,col) = x_coor(row1,col-2) + delta_x;
            end
            
        end
            
    end
end

Best Answer

Related Solutions

MATLAB: How to delete an entire column if any 1 element in that column is above a threshold

MATLAB: Creating a matrix with alternating and increasing values

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