MATLAB: Create a matrix with numbers from vector

matrix manipulation

i have a vector as 
v = [ 1 1 1 2 2 2 3 3 4]
i wanted to create a new matrix as
M = [ 
1 1 1 0 0 0 0 0 0; 
0 0 0 1 1 1 0 0 0;
0 0 0 0 0 0 1 1 0;
0 0 0 0 0 0 0 0 1];
how to do it?

Best Answer

v = [1 1 1 2 2 2 3 3 4];
u=unique(v);
R=arrayfun(@(x)v==u(x),1:numel(u),'un',0);
M=+vertcat(R{:})
Gives:
M =
     1     1     1     0     0     0     0     0     0
     0     0     0     1     1     1     0     0     0
     0     0     0     0     0     0     1     1     0
     0     0     0     0     0     0     0     0     1
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