Create a logical matrix from numerical vector

Maybe the title sounds vague, but I'll try to explain. I have the following vector of size samples-by-1 that contains the numerical values between 0 and 9 (10 values):

V = [3;5;1;2;6;9;7;8;4;0]

Now I want to create a 'logical' matrix from this. So like this:

       0 1 2 3 4 5 6 7 8 9
  M = [0 0 0 1 0 0 0 0 0 0;
       0 0 0 0 0 1 0 0 0 0;
       0 1 0 0 0 0 0 0 0 0;
       0 0 1 0 0 0 0 0 0 0;
       0 0 0 0 0 0 1 0 0 0;
       0 0 0 0 0 0 0 0 0 1;
       0 0 0 0 0 0 0 1 0 0;
       0 0 0 0 0 0 0 0 1 0;
       0 0 0 0 1 0 0 0 0 0;
       1 0 0 0 0 0 0 0 0 0]

What's the easiest way to achieve this?

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/nnet/ref/ind2vec.html

full( ind2vec(V+1).' )

or,

accumarray((1:length(V)).', V+1)

or

maxV = max(V);
LV = length(V);
M = zeros(LV, maxV+1);
M(V * LV + (1:LV).') = 1;

or

 maxV = max(V);
 LV = length(V);
 M = zeros(LV, maxV+1);
 M( sub2ind(size(M), (1:LV).', V+1) ) = 1;

[YT]

Tested with V is a 70.000-by-1 vector

• solution 1, didn't work (Error using ind2vec, The data is not a row vector or cell array of row vectors)
• solution 2, returned samples-by-1 vector with values 1-10.
• solution 3/4, worked. Returned samples-by-10 matrix with values 0/1

Thanks for the fast responses (@all)

[Walter Roberson]

full( ind2vec(V.'+1).' )

or

accumarray([(1:length(V)).', V+1], 1)

[YT]

Easy fix I see. Thanks!