Array interpolation in python?

Question

I have two arrays :

array_x = [x1, x2, x3, x4... xn]
array_y = [y1, y2, y3, y4... yn]

I would like to have a function f(array_x, array_y, value_x) that returns the value_y associated to the value_x by interpolation into the arrays.

How to do that ?

Solution

I think that numpy.interp is exactly what you want. e.g.:

numpy.interp(value_x,array_x,array_y)

Note that here value_x can be a scalar or another array-like value. If it is an array-like value, you will be returned an array of corresponding interpolated values.

Comments

[Adrians Netlis]

Hm... How to write this my own? Some people complain that they got no numpy, so I need this myself...

[mgilson]

Linear interpolation is a pretty well known algorithm. From there, it's just a matter of searching the array (could use bisection) for the elements that bound the value where you want to interpolate to -- With that said, for any real mathematical analysis, numpy seems to be the standard. Is there a reason why those people can't install numpy?

[Adrians Netlis]

When I make game, I wouldn't want to place a tester for numpy(if it is installed) and installer(if it is not). So...