Merge branch 'take'

Author: jreback

doc/source/whatsnew/v0.16.1.txt

@@ -272,7 +272,7 @@ Bug Fixes
 - Bug where ``TimdeltaIndex`` were not properly serialized in fixed ``HDFStore`` (:issue:`9635`)
 - Bug with ``TimedeltaIndex`` constructor ignoring ``name`` when given another ``TimedeltaIndex`` as data (:issue:`10025`).
 - Bug in ``DataFrameFormatter._get_formatted_index`` with not applying ``max_colwidth`` to the ``DataFrame`` index (:issue:`7856`)
-
+- Bug in ``.loc`` with a read-only ndarray data source (:issue:`10043`)
 - Bug in ``groupby.apply()`` that would raise if a passed user defined function either returned only ``None`` (for all input). (:issue:`9685`)
 
 - Bug in plotting continuously using ``secondary_y`` may not show legend properly. (:issue:`9610`, :issue:`9779`)

pandas/src/generate_code.py

@@ -93,12 +93,7 @@ def take_1d_%(name)s_%(dest)s(ndarray[%(c_type_in)s] values,
 
 """
 
-take_2d_axis0_template = """@cython.wraparound(False)
-@cython.boundscheck(False)
-def take_2d_axis0_%(name)s_%(dest)s(%(c_type_in)s[:, :] values,
-                                    ndarray[int64_t] indexer,
-                                    %(c_type_out)s[:, :] out,
-                                    fill_value=np.nan):
+inner_take_2d_axis0_template = """\
     cdef:
         Py_ssize_t i, j, k, n, idx
         %(c_type_out)s fv
@@ -140,12 +135,34 @@ def take_2d_axis0_%(name)s_%(dest)s(%(c_type_in)s[:, :] values,
 
 """
 
-take_2d_axis1_template = """@cython.wraparound(False)
+take_2d_axis0_template = """\
+@cython.wraparound(False)
 @cython.boundscheck(False)
-def take_2d_axis1_%(name)s_%(dest)s(%(c_type_in)s[:, :] values,
+cdef inline take_2d_axis0_%(name)s_%(dest)s_memview(%(c_type_in)s[:, :] values,
+                                                    int64_t[:] indexer,
+                                                    %(c_type_out)s[:, :] out,
+                                                    fill_value=np.nan):
+""" + inner_take_2d_axis0_template + """
+
+@cython.wraparound(False)
+@cython.boundscheck(False)
+def take_2d_axis0_%(name)s_%(dest)s(ndarray[%(c_type_in)s, ndim=2] values,
                                     ndarray[int64_t] indexer,
                                     %(c_type_out)s[:, :] out,
                                     fill_value=np.nan):
+    if values.flags.writeable:
+        # We can call the memoryview version of the code
+        take_2d_axis0_%(name)s_%(dest)s_memview(values, indexer, out,
+                                                fill_value=fill_value)
+        return
+
+    # We cannot use the memoryview version on readonly-buffers due to
+    # a limitation of Cython's typed memoryviews. Instead we can use
+    # the slightly slower Cython ndarray type directly.
+""" + inner_take_2d_axis0_template
+
+
+inner_take_2d_axis1_template = """\
     cdef:
         Py_ssize_t i, j, k, n, idx
         %(c_type_out)s fv
@@ -165,9 +182,36 @@ def take_2d_axis1_%(name)s_%(dest)s(%(c_type_in)s[:, :] values,
                 out[i, j] = fv
             else:
                 out[i, j] = %(preval)svalues[i, idx]%(postval)s
-
 """
 
+take_2d_axis1_template = """\
+@cython.wraparound(False)
+@cython.boundscheck(False)
+cdef inline take_2d_axis1_%(name)s_%(dest)s_memview(%(c_type_in)s[:, :] values,
+                                                    int64_t[:] indexer,
+                                                    %(c_type_out)s[:, :] out,
+                                                    fill_value=np.nan):
+""" + inner_take_2d_axis1_template + """
+
+@cython.wraparound(False)
+@cython.boundscheck(False)
+def take_2d_axis1_%(name)s_%(dest)s(ndarray[%(c_type_in)s, ndim=2] values,
+                                    ndarray[int64_t] indexer,
+                                    %(c_type_out)s[:, :] out,
+                                    fill_value=np.nan):
+
+    if values.flags.writeable:
+        # We can call the memoryview version of the code
+        take_2d_axis1_%(name)s_%(dest)s_memview(values, indexer, out,
+                                                fill_value=fill_value)
+        return
+
+    # We cannot use the memoryview version on readonly-buffers due to
+    # a limitation of Cython's typed memoryviews. Instead we can use
+    # the slightly slower Cython ndarray type directly.
+""" + inner_take_2d_axis1_template
+
+
 take_2d_multi_template = """@cython.wraparound(False)
 @cython.boundscheck(False)
 def take_2d_multi_%(name)s_%(dest)s(ndarray[%(c_type_in)s, ndim=2] values,