Change Legend diagram in matlab

问题

I have some code that basically does this:

for i = 1:length(ReliabilityStruct)
    if (FailureFlags(i) == 0) 
        plot(X(i), Y(i), '.b');
    elseif (FailureFlags(i) == 1)
        plot(X(i), Y(i), 'or');
    elseif (FailureFlags(i) == 2)
        plot(X(i), Y(i), 'og');
    elseif (FailureFlags(i) == 3)
        plot(X(i), Y(i), 'ok');
    else
        fprintf('\nUnknown Flag, check Data\n')
        return
    end
end
drawnow;
legend('Recovery', '1', '2', '3');

So my aim is to make a graph that has different symbols for different flags. See below:

As you can see, the Legend doesn't exactly fit the data. How can you change each of the legend entries to fix this up? Alternatively, is there a better way to approach this?

回答1:

I think you can use something like this (added bonus is that you avoid loops!):

ind = FailureFlags==0;
plot(X(ind), Y(ind), '.b');

ind = FailureFlags==1;
plot(X(ind), Y(ind), 'or');

ind = FailureFlags==2;
plot(X(ind), Y(ind), 'og');

ind = FailureFlags==3;
plot(X(ind), Y(ind), 'ok');

legend('Recovery', '1', '2', '3');

回答2:

Give this a try. In your loop make an assignment for each plot as follows:

 p1=plot(X(i), Y(i), '.b');
elseif (FailureFlags(i) == 1)
 p2=plot(X(i), Y(i), 'or');
elseif (FailureFlags(i) == 2)
 p3=plot(X(i), Y(i), 'og');
elseif (FailureFlags(i) == 3)
 p4=plot(X(i), Y(i), 'ok');

Then you can use legend for the specific things:

legend([p1 p2],'stuff','morestuff')

回答3:

Remember that you can refer to the usage for any function using help command. For your case, the help legend will give you usage examples like following.

legend(H,string1,string2,string3, ...) puts a legend on the plot
containing the handles in the vector H using the specified strings as
labels for the corresponding handles.

Thus, you can get the plot handler by assign the plot to a variable, such as p1=plot(X(i), Y(i), '.b');. And then draw the legend by invoke the command with handlers as first parameter, like legend([p1], 'something').

来源：https://stackoverflow.com/questions/14995643/change-legend-diagram-in-matlab

标签

matlab

figure