How to create a colormap attributing specific colour to each element?

Hi everyone!

I have an array A,

A = [ 1 2 3 4

2 2 3 1

1 1 4 2];

I want to create a colormap but each element needs to be colored in a specific colour, for example, 1 is blue, 2 is black, 3 is green and 4 is yellow.

Thanks

[Stephen23]

See:

https://www.mathworks.com/matlabcentral/answers/441286-how-to-handle-a-colormap-with-multiple-patches

Answer 1

[Matt Gaidica]

Given these data, I would do this.

A = [ 1 2 3 4
     2 2 3 1
     1 1 4 2];
cmap = jet(max(A(:)));

figure;
imagesc(A);
colormap(cmap);
colorbar;

Answer 2

[Stephen23]

A = [1,2,3,4;2,2,3,1;1,1,4,2];
map = [0,0,1;0,0,0;0,1,0;1,1,0]; % [blue;black;green;yellow]
imagesc(A,[1,4]) % better to set the color limits.
colormap(map)

[Cassio Lima]

Thank you guys. It helped a lot :D