MAINT: Use normalize_axis_index in all python axis checking

As a result, some exceptions change from ValueError to IndexError

This also changes the exception types raised in places where
normalize_axis_index is not quite appropriate

1 files changed, 3 insertions, 8 deletions

diff --git a/numpy/polynomial/chebyshev.py b/numpy/polynomial/chebyshev.py
index 3babb8fc2..49d0302e0 100644
--- a/numpy/polynomial/chebyshev.py
+++ b/numpy/polynomial/chebyshev.py
@@ -90,6 +90,7 @@ from __future__ import division, absolute_import, print_function
 import warnings
 import numpy as np
 import numpy.linalg as la
+from numpy.core.multiarray import normalize_axis_index
 
 from . import polyutils as pu
 from ._polybase import ABCPolyBase
@@ -936,10 +937,7 @@ def chebder(c, m=1, scl=1, axis=0):
         raise ValueError("The order of derivation must be non-negative")
     if iaxis != axis:
         raise ValueError("The axis must be integer")
-    if not -c.ndim <= iaxis < c.ndim:
-        raise ValueError("The axis is out of range")
-    if iaxis < 0:
-        iaxis += c.ndim
+    iaxis = normalize_axis_index(iaxis, c.ndim)
 
     if cnt == 0:
         return c
@@ -1064,10 +1062,7 @@ def chebint(c, m=1, k=[], lbnd=0, scl=1, axis=0):
         raise ValueError("Too many integration constants")
     if iaxis != axis:
         raise ValueError("The axis must be integer")
-    if not -c.ndim <= iaxis < c.ndim:
-        raise ValueError("The axis is out of range")
-    if iaxis < 0:
-        iaxis += c.ndim
+    iaxis = normalize_axis_index(iaxis, c.ndim)
 
     if cnt == 0:
         return c