select a portion of the matrix

Hi! I have the matrix 'matrix_C'. How can I stop (in this case) at the fifth row, i.e. when column 2,3,4 have 0 and column 5 a number?

Answer 1

[Star Strider]

One approach —

LD = load('matrix_C.mat');
C = LD.C

C = 7×5

81 43 134 120 297 82 32 77 73 182 83 0 50 45 116 84 0 0 35 76 85 0 0 0 60 86 0 0 0 44 87 0 0 0 41

idx = find(sum(C(:,[2 3 4])==0,2)==3, 1);
Result = C(1:idx,:)

Result = 5×5

81 43 134 120 297 82 32 77 73 182 83 0 50 45 116 84 0 0 35 76 85 0 0 0 60

.

Answer 2

[the cyclist]

The following does what you asked for, for this matrix. The "rule" you specified was not perfectly clear to me, though, so this may not generalize to other matrices in the way you want.

load("matrix_C.mat","C")
C

C = 7×5

81 43 134 120 297 82 32 77 73 182 83 0 50 45 116 84 0 0 35 76 85 0 0 0 60 86 0 0 0 44 87 0 0 0 41

indexToLastRow = find(all(C(:,2:4)==0 & C(:,5)~=0,2),1);

C(1:indexToLastRow,:)

ans = 5×5

81 43 134 120 297 82 32 77 73 182 83 0 50 45 116 84 0 0 35 76 85 0 0 0 60