Displaying a value in the plot

Hello,

I am plotting x vs y and I am taking out the maximum value of x with max(x)

Now I want to display this maximum value of x together with some text in a legend. I am trying to use num2str.. I am not sure if I am the right track.

Answer 1

[Star Strider]

I would use sprintf, for example:

x = linspace(-5,5);
y = 5-(x+2).^2;
[maxy,idx] = max(y);

figure(1)
plot(x, y, x(idx),y(idx),'pr')
legend('y(x)', sprintf('Maximum y = %0.3f',maxy))
axis([xlim    min(y) max(y)+1])

[Ivan Mich]

Exsuse me, but in this example we want one value, the maxy. If we want to put min(y) too (which means 2 values) what changes of this command we shall do?

[Star Strider]

@Ravnalis Michael —

Either change the call from max to min (and the rest of the code appropriately), or add a separate min call, similar to the max call.

Answer 2

[dpb]

Well, we don't know if you're "on the right track" or not, either since you didn't show what you tried nor indicate what the problem was, if any...

num2str is fine (as would be sprintf) to use to format a value for display with additional text using the format string. To display it, you use text

You can also use annotation object for an arrow pointing to the value and so on.

doc text % for details