# Interpolate between specific values in a data set

8 views (last 30 days)
Reece Smith on 8 May 2022
Commented: the cyclist on 8 May 2022
I am having trouble trying to figure out how to interpolate between specific y values for 2 given x values from excel.
For example in excel:
X Y
1 0.2
2.2 0.35
3 0.4
4 0.5
then given an X value of 3.5 from a matlab output I would like to find the corresponding Y value, in this case it would be 0.45. Then store that and use that in the future. I am not sure how to search for where 3.5 would sit within the X column and then find the surrounding values to do the interpolation.

the cyclist on 8 May 2022
Edited: the cyclist on 8 May 2022
You can use the interp1 function to do interpolation.
x = [1, 2.2, 3, 4];
y = [0.2, 0.35, 0.4, 0.5];
x0 = 3.5;
y0 = interp1(x,y,x0)
y0 = 0.4500
the cyclist on 8 May 2022
@Reece Smith, if you can upload an example of the data and code that give a different result from what you expect, we could try to help you understand the difference.

R2020b

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