How can I give a different legend for each element of a vector in a scatter plot?

Hi! I'm a beginner at Matlab and I'm having trouble to assign legend to my data in plots. Let's say I have three samples named 'a', 'b', 'c' which have X values of A e y values of B.

A=[1:3]; B=[9:11];

(example: sample 'a' has a value of 1 in the X axis and 9 in the y axis)

I created a string C=['a,b,c'] for the legend, but when I plot them and insert legend I don't get what I mean. This is what I did:

scatter(A,B); legend(C); And this is what Matlab returned:

What I wanted was that each marker could be assigned a different legend, since they refer to different samples. When I created separated variables for each sample, I could do what I wanted, but I'm sure there might have a simpler way of doing it.

p.s.: This is just an example, my real data might have up to 130 samples!

Answer 1

[Walter Roberson]

You cannot do that with scatter() and legend() in a single scatter call. scatter() only creates a single graphics object per call.

If you want to label the object "near" the dot, then consider

scatter(A,B); text(A,B,{'  a','  b','  c'})

Notice the two extra spaces I put before each letter: that is to move the letter away from the dot.

If you want to use legend then:

for K = 1 : length(A);scatter(A(K),B(K)); hold on; end; legend({'a','b','c'})

Answer 2

[Star Strider]

You have to plot the individual data (or groups of data) separately, and you need to use a cell array for the legend, since the square brackets [] concatenate string arrays:

A=[1:3]; B=[9:11];

C={'a', 'b', 'c'};

figure(1)
hold on
for k1 = 1:length(A)
    scatter(A(k1),B(k1))
end
hold off
legend(C)

[Rayza Rosa Tavares Rodrigues]

Thank you very much! It worked really well!

[Star Strider]

My pleasure!

If my Answer solved your problem, please Accept it.

Answer 3

[Azzi Abdelmalek]

A=[1:3];
B=[9:11];
figure;
hold on
for k=1:numel(A)
scatter(A,B,'facecolor','b')
end
hold off
legend({'a','b','c'})