Assining fixed color for zero value

i have a 2D matrix A(i,j). each value in this matrix can be the integers between 1:n for examle. some cells are equal to zero and i need an image plot of A but with black color for zero values. is it possible in matlab?

Answer 1

[Adam]

Define a colourmap of size n, assuming n is not huge, and then add black to the front of it

n = 7;
colourmap = [0 0 0; parula( n )];

Then, e.g.

myData = randi(n, 20 ) - 1;
figure; imagesc( myData );
colormap( colourmap )
caxis( [-0.5 n + 0.5] )

[Sarem.N]

Thats exactly what i want. Thanks a lot