From 02adbd82b77ccb0a64539691a24d031497c0d91b Mon Sep 17 00:00:00 2001
From: MomIsBestFriend <>
Date: Wed, 18 Mar 2020 14:46:17 +0200
Subject: [PATCH] PERF: Using Numpy C-API when calling `np.arange`

---
 pandas/_libs/internals.pyx | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pandas/_libs/internals.pyx b/pandas/_libs/internals.pyx
index 5545302fcbfc4..63f076b7ee993 100644
--- a/pandas/_libs/internals.pyx
+++ b/pandas/_libs/internals.pyx
@@ -308,7 +308,10 @@ cdef slice_getitem(slice slc, ind):
             return slice(s_start, s_stop, s_step)
 
     else:
-        return np.arange(s_start, s_stop, s_step, dtype=np.int64)[ind]
+        # NOTE:
+        # this is the C-optimized equivalent of
+        # `np.arange(s_start, s_stop, s_step, dtype=np.int64)[ind]`
+        return cnp.PyArray_Arange(s_start, s_stop, s_step, NPY_INT64)[ind]
 
 
 @cython.boundscheck(False)