DOC: correction to numpy.pad docstring (#13149)

* DOC: fix mistatement in numpy.pad docstring

1 files changed, 3 insertions, 5 deletions

diff --git a/numpy/lib/arraypad.py b/numpy/lib/arraypad.py
index 570f86969..07146f404 100644
--- a/numpy/lib/arraypad.py
+++ b/numpy/lib/arraypad.py
@@ -694,9 +694,8 @@ def pad(array, pad_width, mode='constant', **kwargs):
     think about with a rank 2 array where the corners of the padded array
     are calculated by using padded values from the first axis.
 
-    The padding function, if used, should return a rank 1 array equal in
-    length to the vector argument with padded values replaced. It has the
-    following signature::
+    The padding function, if used, should modify a rank 1 array in-place. It
+    has the following signature::
 
         padding_func(vector, iaxis_pad_width, iaxis, kwargs)
 
@@ -704,7 +703,7 @@ def pad(array, pad_width, mode='constant', **kwargs):
 
         vector : ndarray
             A rank 1 array already padded with zeros.  Padded values are
-            vector[:pad_tuple[0]] and vector[-pad_tuple[1]:].
+            vector[:iaxis_pad_width[0]] and vector[-iaxis_pad_width[1]:].
         iaxis_pad_width : tuple
             A 2-tuple of ints, iaxis_pad_width[0] represents the number of
             values padded at the beginning of vector where
@@ -766,7 +765,6 @@ def pad(array, pad_width, mode='constant', **kwargs):
     ...     pad_value = kwargs.get('padder', 10)
     ...     vector[:pad_width[0]] = pad_value
     ...     vector[-pad_width[1]:] = pad_value
-    ...     return vector
     >>> a = np.arange(6)
     >>> a = a.reshape((2, 3))
     >>> np.pad(a, 2, pad_with)