How to plot two columns of a repeated value column from the same matrix?

if A is a 10x4 matrix with some repeated values along A(:,1) like:

A=[1    10    13    31
1    15    33    22
1    43    3    12
1    3    54    12
2    45    34    13
2    44    31    12
2    32    35    11
3    34    13    31
3    34    34    12
4    35    23    43];

I want to plot scatter(A(:,4),A(:,3)) with the same dot color for every value of A(:,1) that is repeated. For instance a manual plot of A would be:

scatter(A(1:4,4),A(1:4,3),'filled','r')
hold on
scatter(A(5:7,4),A(5:7,3),'filled','b')
hold on
scatter(A(8:9,4),A(8:9,3),'filled','k')
hold on
scatter(A(10,4),A(10,3),'filled','g')

Which plots

I used manually the colors red, blue, black and green for the first 4 repeated values. But to analize a big dataset, i would like to plot the scatter using a colorbar for the increasing A(:,1) repeated values.

Answer 1

[David Hill]

sz=25;
scatter(A(:,4),A(:,3),sz,A(:,1),'filled');