# How can I determine conditions and interpolate where necessary?

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Hello
Assumingly we have a conditional state for most of the y values on axis and need to interpolate where necessary or where there are no conditions.
For example if we say that, while y = 3 then var = 5, what if y = 2.5, var = ??
We have information that for every y value equals to 3 the var is equal to 5 but we don't have information for y equals to 2.5 regarding the corresponding var value. In this case, an interpolation should come.
Can you please provide some code ideas?
Thank you
##### 2 CommentsShowHide 1 older comment
Stelios Fanourakis on 31 Oct 2019
I have x data which is the length of an object. Y data which is the height or the object's thickness. X data is same for both sets. Y axis data are different among sets. There is a third variable that is linked to y values. Y values are strain, 3rd variable is force and X is length of the object. Based on y values the force is changing. So different y values need to interpolate force values.

Dimitris Kalogiros on 31 Oct 2019
Stelio
A good solution for you problem is to use polynomial interpolation.
Stelios Fanourakis on 1 Nov 2019
I know polynomial interpolation as I have used it before for other of my tasks. It doesn't explain me how it will interpolate the force for every different y value. Even if there are 2 variables force/thickness (y values) how can this be linked with the stationary x values. X values do not change. They are the same. Only y values and forces are changing. But I think generally polynomials is a good idea. It just needs a small modification to suit my needs