MATLAB: Reading Flags in a matrix

matricesmatrixmatrix arraymatrix manipulation

I have this data from an input file below I have separated them by blocks the first block (rows 1 through 7) is my node block where column 4 are flags. When there is a 0 that means that the value in column 4 is a force and when there is a 1 that means the value in column 4 is a displacement.
1 3.0 0 0
2 2.0 0 0
3 0.5 1 0.001
4 0.5 0 5000
5 4.0 0 0
6 8.25 1 0
7 6.5 0 -2000
Right now I have this Code:
    X                 = NodeBlock(:,3)
      if X == 0
        U = NodeBlock(:,X)
      else X == 1
        F = NodeBlock(:,X)
      end
and its not working right, I just want it to compute that if X (the values in column 3) is 0 then Column 4 is a U (displacement) and vice versa for my Forces. I need this to help me set up my K Matrix in order for it to solve for either F or U.
Keep in mind that this is only sample data and the amount of nodes are variable which is why I am trying to keep it in vector format. The amount of columns are fixed
Thanks,
90% Newbie

Best Answer

NodeBlock=[1 3.0 0 0
2 2.0 0 0
3 0.5 1 0.001
4 0.5 0 5000
5 4.0 0 0
6 8.25 1 0
7 6.5 0 -2000]
X=logical(NodeBlock(:,3));
U= NodeBlock(~X,4);
F=NodeBlock(X,4)
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