Product features · Clamped linear interpolation

from math import isfinite

def interpolate(points, query):
    def valid(x):
        return type(x) in (int, float) and abs(x) <= 10**12 and isfinite(x)
    if type(points) is not list or len(points) < 2 or not valid(query):
        raise ValueError("knots.input")
    if any(type(p) not in (list, tuple) or len(p) != 2 or
           not all(valid(v) for v in p) for p in points):
        raise ValueError("knots.point")
    if any(a[0] >= b[0] for a,b in zip(points, points[1:])):
        raise ValueError("knots.order")
    if query <= points[0][0]:
        return points[0][1]
    for (x0,y0),(x1,y1) in zip(points, points[1:]):
        if query <= x1:
            t = (query-x0)/(x1-x0)
            return (1-t)*y0+t*y1
    return points[-1][1]