How to put a variable in a legend without it being in the range of the plot?

When i try to place a variable in the legend of a plot, lets say the slope of a function. Even if I, from other examples use the sprintf(), I get Warning: Ignoring extra legend entries. What am I doing wrong? slope = 10000000000; x = 1:5; y = 6:10; a = 11:15; b = 16:20; slopestr = sprintf('slope is %f',slope); figure(1); plot(x,y); hold on; plot(a,b); legend('curve1','curve2',slopestr); hold off;

[Alexander Björkengren]

I ended up plotting the variables with white color then changing the axes limits to get the original appearence. Then sprintf() worked fine for putting the variables in the legend

Answer 1

[VBBV]

slope = 3;
x = 1:5;
y = 6:10;
a = 11:15;
b = 16:20;
slopestr = sprintf('slope is %f',slope)

slopestr = 'slope is 3.000000'

figure(1);
plot(x,y);
hold on;
plot(a,b);
plot(slope,'o')
legend('curve1','curve2',slopestr);
hold off;

[VBBV]

plot the value of slope in graph, then it works

[Alexander Björkengren]

Im sorry, the example I provided were not exactly in line with my question. Lets say that the slope value instead of 3 were 100000000. Then the plot would show the whole interval and the other data would not be visible anymore.

[VBBV]

you can plot the slope value in terms of log function, if you want all in one graph, since the value of slope is very large !

slope = 1e9;  % a very high value
x = 1:5;
y = 6:10;
a = 11:15;
b = 16:20;
slopestr = sprintf('slope is %0.1f',slope)

slopestr = 'slope is 1000000000.0'

figure(1);
plot(x,y);
hold on;
plot(a,b);
plot(log(slope),'bo','markersize',8) % plot using log value of slope
text(min(x)+0.5,log(slope),'Slope')
% axis([0 15 0 1e9])  % this is not good option 
legend('curve1','curve2',slopestr);
hold off;

[VBBV]

you can try plotting x,y,a,b and slope variables in log function instead to represent all in one graph

slope = 1e9;  % a very high value
x = 1:5;
y = 6:10;
a = 11:15;
b = 16:20;
slopestr = sprintf('slope is %0.1f',slope)

slopestr = 'slope is 1000000000.0'

figure(1);
semilogx(x,y);
hold on;
semilogx(a,b);
plot(log(slope),'bo','markersize',8) % plot using log value of slope
text(min(x)+0.1,log(slope),'Slope')
grid 
% axis([0 15 0 1e9])  % this is not good option 
legend('curve1','curve2',slopestr);
hold off;