added `clip` to `linear_interpolate`

CHANGELOG.md

 # v2.14.15
 
 * added `Vector`
+* added `clip` to `linear_interpolate`

satella/__init__.py

-__version__ = '2.14.15_a2'
+__version__ = '2.14.15'

satella/coding/transforms/interpol.py

@@ -3,7 +3,8 @@ from satella.coding.typing import U, K
 import bisect
 
 
-def linear_interpolate(series: tp.Sequence[tp.Tuple[K, U]], t: K) -> U:
+def linear_interpolate(series: tp.Sequence[tp.Tuple[K, U]], t: K,
+                       clip: bool = False) -> U:
     """
     Given a sorted (ascending) series of (t_value, y_value) interpolating linearly a function of
     y=f(t) compute a linear approximation of f at t
@@ -13,13 +14,21 @@ def linear_interpolate(series: tp.Sequence[tp.Tuple[K, U]], t: K) -> U:
 
     :param series: series of (t, y) sorted by t ascending
     :param t: t to compute the value for
+    :param clip: if set to True, then values t: t<t_min f(t_min) will be returned
+        and for values t: t>t_max f(t_max) will be returned
     :return: return value
     :raise ValueError: t was smaller than t_min or greater than t_max
     """
     if t < series[0][0]:
-        raise ValueError('t smaller than t_min')
+        if clip:
+            return series[0][1]
+        else:
+            raise ValueError('t smaller than t_min')
     if t > series[-1][0]:
-        raise ValueError('t greater than t_max')
+        if clip:
+            return series[-1][1]
+        else:
+            raise ValueError('t greater than t_max')
 
     if t == series[0][0]:
         return series[0][1]

tests/test_coding/test_transforms.py

@@ -17,6 +17,8 @@ class TestTransforms(unittest.TestCase):
         self.assertEqual( linear_interpolate([(0, 10), (10, 20), (20, 10)], 15), 15)
         self.assertRaises(ValueError, lambda: linear_interpolate([(0, 10), (10, 20)], 30))
         self.assertRaises(ValueError, lambda: linear_interpolate([(0, 10), (10, 20)], -2))
+        self.assertEqual(linear_interpolate([(0, 10), (10, 20)], 30, True), 20)
+        self.assertEqual(linear_interpolate([(0, 10), (10, 20)], -2, True), 10)
 
     def test_base64(self):
         a = b64encode(b'test')