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Hi. Suppose I have the matrix A of size (m*n).

A = [12 44

93 43

128 44

145 41

180 41

220 40

280 40];

also I have the vector V e.g.

V = [13 20 70 90 95 100 102 110 129 130 145 158 170 185 190 200 207 220 270 280 285 290];

I want to find which one of the rows of matrix A based on its first column values is right after and right before the values of vector V, and if one of the values of the first column of matrix A is equal to the values of vector V, I want to find that row.

For example :

A(2,1) is right before V(5) and V(6) and V(7) and V(8)

A(3,1) is right after V(5) and V(6) and V(7) and V(8)

and in case of equality I want to find this

A(4,1) = V(11)

A(5,1) = V(18)

A(7,1) = V(20)

In other words, I want to find exactly which members of vector V are between which members of first column of matrix A with their indices like this :

V(1) and V(2) and V(3) and V(4) is between A(1,1) and A(2,1)

Thanks for your help.

Guillaume
on 7 Nov 2017

An alternative method that does not involve loops (or arrayfun) but is not necessary faster than KL's:

comp = abs(A(:, 1) - V);

comp(A(:, 1) > V) = inf;

[~, beforeVidx] = min(comp, [], 2);

isequaltoV = A(:, 1) == V(beforeVidx)';

%for display only:

table(A, beforeVidx, isequaltoV)

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