How do I extract a certain datapoint from a curve?

I would like to extract a specific data point from curves. Attached an example curve. Need to find, when x=14.3, what's the value of y?

Need help to achieve this. Many thanks.

Answer 1

[Star Strider]

Try this:

x = linspace(0, 100);                           % Create Vector
y = 25 - 10*sin(2*pi*x/100);                    % Create Vector

xq = 14.3;
yq = interp1(x, y, xq);                         % Interpolate To Determine Value

figure
plot(x, y)
hold on
plot(xq, yq, '+r')
hold off
ylim([0 40])
text(xq, yq, sprintf('\\leftarrow y(%.1f) = %.1f', xq, yq), 'HorizontalAlignment','left','VerticalAlignment','middle')

.

[Ling Li]

Thank you so much, Star Stider.

My task is more complex than certain type of curve. My curves are different patterns. I attached another curve here. I don't know if I need to export the datasets from the curve first, then get the specific datapoint.

[Star Strider]

My approach should work regardless of the curve.

I created my vectors to demonstrate the approach, and that the code works. Use your own vectors with my code.

[Ling Li]

Thank you so so much, Star Straider. I tried with my vectors, your code works great.

[Star Strider]

As always, my pleasure!

Thank you!