Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 69 insertions, 0 deletions

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+.. Licensed to the Apache Software Foundation (ASF) under one
+.. or more contributor license agreements.  See the NOTICE file
+.. distributed with this work for additional information
+.. regarding copyright ownership.  The ASF licenses this file
+.. to you under the Apache License, Version 2.0 (the
+.. "License"); you may not use this file except in compliance
+.. with the License.  You may obtain a copy of the License at
+
+..   http://www.apache.org/licenses/LICENSE-2.0
+
+.. Unless required by applicable law or agreed to in writing,
+.. software distributed under the License is distributed on an
+.. "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+.. KIND, either express or implied.  See the License for the
+.. specific language governing permissions and limitations
+.. under the License.
+
+.. currentmodule:: pyarrow.compute
+.. _compute:
+
+=================
+Compute Functions
+=================
+
+Arrow supports logical compute operations over inputs of possibly
+varying types.  Many compute functions support both array (chunked or not)
+and scalar inputs, but some will mandate either.  For example,
+``sort_indices`` requires its first and only input to be an array.
+
+Below are a few simple examples:
+
+   >>> import pyarrow as pa
+   >>> import pyarrow.compute as pc
+   >>> a = pa.array([1, 1, 2, 3])
+   >>> pc.sum(a)
+   <pyarrow.Int64Scalar: 7>
+   >>> b = pa.array([4, 1, 2, 8])
+   >>> pc.equal(a, b)
+   <pyarrow.lib.BooleanArray object at 0x7f686e4eef30>
+   [
+     false,
+     true,
+     true,
+     false
+   ]
+   >>> x, y = pa.scalar(7.8), pa.scalar(9.3)
+   >>> pc.multiply(x, y)
+   <pyarrow.DoubleScalar: 72.54>
+
+These functions can do more than just element-by-element operations.
+Here is an example of sorting a table:
+
+    >>> import pyarrow as pa
+    >>> import pyarrow.compute as pc
+    >>> t = pa.table({'x':[1,2,3],'y':[3,2,1]})
+    >>> i = pc.sort_indices(t, sort_keys=[('y', 'ascending')])
+    >>> i
+    <pyarrow.lib.UInt64Array object at 0x7fcee5df75e8>
+    [
+      2,
+      1,
+      0
+    ]
+
+
+
+.. seealso::
+
+   :ref:`Available compute functions (C++ documentation) <compute-function-list>`.