Erratic behavior of Legend function

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I was working on a matlab project and found strange behavior of legend function. I am posting similar code to reproduce the issue (Kindly ignore the weird looking plot). below is the code

X=rand(3,100);
a=rand(3,100);
b=rand(3,100);
figure(1); hold on;
plot(0.17663,'m');
plot(1.223,'y');
plot(X,a,'r');
plot(X,b,'g');
legend({'plot1','plot2','plot3','plot4'});

so my question is the legend in the picture shows the same color for plot 3 and plot4. Instead it should show red and green respectively. Please help me to sort this out. Thanks.

Answer 1

[Geoff Hayes]

Priyanka - when you plot X vs a as

 plot(X,a,'r');

remember that X and a are 3x100 matrices and so you are in fact plotting 100 curves each with their own handles. So if you were to do

 h = plot(X,a,'r');

h would be a 100x1 array and all 100 curves/lines would be drawn in red. When you call

 legend({'plot1','plot2','plot3','plot4'});

plot3 and plot4 correspond to two of the 100 curves drawn in red...which explains your observation.

What does your X and a data correspond to? Could they be reshaped to 1x300 arrays instead?