replace duplicate value by 0 in matrix or vector

How do we replace duplicate value by 0 in matrix or vector ?

for example

Input:

b = 1 2 1 3

Output::

b= 1 2 0 3

Thanks

Answer 1

[Andrei Bobrov]

 b = [1 2 1 3];
 
 [a,c] = unique(b,'first');
 out = zeros(size(b));
 out(c) = a;

[Mira le]

thank you

Answer 2

[Adam]

[C,ia] = unique( b );
b( setdiff( 1:numel(b), ia ) ) = 0;

Answer 3

[Jos (10584)]

% for small vectors:
b = [1 2 1 3 2 1 4 2]
b(sum(triu(b == b')) > 1) = 0