1 files changed, 35 insertions, 9 deletions

diff --git a/numpy/lib/function_base.py b/numpy/lib/function_base.py
index 2992e92bb..e2a8f4bc2 100644
--- a/numpy/lib/function_base.py
+++ b/numpy/lib/function_base.py
@@ -9,24 +9,23 @@ except ImportError:
 import re
 import sys
 import warnings
-import operator
 
 import numpy as np
 import numpy.core.numeric as _nx
-from numpy.core import linspace, atleast_1d, atleast_2d, transpose
+from numpy.core import atleast_1d, transpose
 from numpy.core.numeric import (
     ones, zeros, arange, concatenate, array, asarray, asanyarray, empty,
     empty_like, ndarray, around, floor, ceil, take, dot, where, intp,
-    integer, isscalar, absolute, AxisError
+    integer, isscalar, absolute
     )
 from numpy.core.umath import (
-    pi, multiply, add, arctan2, frompyfunc, cos, less_equal, sqrt, sin,
-    mod, exp, log10, not_equal, subtract
+    pi, add, arctan2, frompyfunc, cos, less_equal, sqrt, sin,
+    mod, exp, not_equal, subtract
     )
 from numpy.core.fromnumeric import (
-    ravel, nonzero, sort, partition, mean, any, sum
+    ravel, nonzero, partition, mean, any, sum
     )
-from numpy.core.numerictypes import typecodes, number
+from numpy.core.numerictypes import typecodes
 from numpy.core.function_base import add_newdoc
 from numpy.lib.twodim_base import diag
 from .utils import deprecate
@@ -36,7 +35,6 @@ from numpy.core.multiarray import (
     )
 from numpy.core.umath import _add_newdoc_ufunc as add_newdoc_ufunc
 from numpy.compat import long
-from numpy.compat.py3k import basestring
 
 if sys.version_info[0] < 3:
     # Force range to be a generator, for np.delete's usage.
@@ -1090,7 +1088,7 @@ def gradient(f, *varargs, **kwargs):
         return outvals
 
 
-def diff(a, n=1, axis=-1):
+def diff(a, n=1, axis=-1, prepend=np._NoValue, append=np._NoValue):
     """
     Calculate the n-th discrete difference along the given axis.
 
@@ -1108,6 +1106,12 @@ def diff(a, n=1, axis=-1):
     axis : int, optional
         The axis along which the difference is taken, default is the
         last axis.
+    prepend, append : array_like, optional
+        Values to prepend or append to "a" along axis prior to
+        performing the difference.  Scalar values are expanded to
+        arrays with length 1 in the direction of axis and the shape
+        of the input array in along all other axes.  Otherwise the
+        dimension and shape must match "a" except along axis.
 
     Returns
     -------
@@ -1176,6 +1180,28 @@ def diff(a, n=1, axis=-1):
     nd = a.ndim
     axis = normalize_axis_index(axis, nd)
 
+    combined = []
+    if prepend is not np._NoValue:
+        prepend = np.asanyarray(prepend)
+        if prepend.ndim == 0:
+            shape = list(a.shape)
+            shape[axis] = 1
+            prepend = np.broadcast_to(prepend, tuple(shape))
+        combined.append(prepend)
+
+    combined.append(a)
+
+    if append is not np._NoValue:
+        append = np.asanyarray(append)
+        if append.ndim == 0:
+            shape = list(a.shape)
+            shape[axis] = 1
+            append = np.broadcast_to(append, tuple(shape))
+        combined.append(append)
+
+    if len(combined) > 1:
+        a = np.concatenate(combined, axis)
+
     slice1 = [slice(None)] * nd
     slice2 = [slice(None)] * nd
     slice1[axis] = slice(1, None)