Multiple legends with a variable in a figure legend

Hi all,

I am trying to plot a figure with 3 curves. I need legends to the figures with varibales as legends. Here is my try. Please correct it.

    figure(), 
    plot(x1, y1,'o', x2, y2, 'x' , coeffs(1)+x2, coeffs(2)+y2,'+')
    legend('x1-y1; i-10:i','x2-y2; i+1:i+11', 'interpolated');

The above figure works fine. But need to add "i" value from the program. Hence I tried methods as follows

    plot(x1, y1,'o', 'DisplayName', sprintf('x1-y1;   i-10:i; i=%d', i), ...
    x2, y2,'x', 'DisplayName', sprintf('x2-y2; i+1:i+11; i=%d', i), ...
    coeffs(1)+x2,coeffs(2)+y2,'+','DisplayName',sprintf('Interpolated; i=%d', i));

The error is

Error using plot String argument is an unknown option.

Thanks for your attention...

Answer 1

[Geoff Hayes]

Raj - the code

 plot(x1, y1,'o', 'DisplayName', sprintf('x1-y1;   i-10:i; i=%d', i), ...
      x2, y2,'x', 'DisplayName', sprintf('x2-y2; i+1:i+11; i=%d', i), ...
      coeffs(1)+x2,coeffs(2)+y2,'+','DisplayName',sprintf('Interpolated; i=%d', i));

is failing because the inputs to plot do not meet the input specification for this function. From plot, we see that a call with multiple inputs is given by

 plot(X1,Y1,LineSpec1,...,Xn,Yn,LineSpecn)

The 'DisplayName' doesn't seem to be one of those line spec properties. Note that even the simpler

plot(x1, y1,'o', 'DisplayName', sprintf('x1-y1;   i-10:i; i=%d', i), x2, y2,'x')

generates the same error.

Since the original code worked, why not combine it with the sprintf as

 legend(sprintf('x1-y1; %d:%d',i-10,i),sprintf('x2-y2; %d:%d',i+1,i+11), 'interpolated');

[Raj Raj]

Thanks for you input. It worked..