!24 Add map_reduce function

From: @zhang-liang-pengkun 
Reviewed-by: @Charlie_li 
Signed-off-by: @Charlie_li

0003-Add-map_reduce-function-196.patch

@@ -0,0 +1,166 @@
+From edfb4704efe9bdb2dc6022fb4b665c62a1525a2c Mon Sep 17 00:00:00 2001
+From: Bo Bayles <bbayles@gmail.com>
+Date: Tue, 20 Feb 2018 06:04:55 -0600
+Subject: [PATCH] Add map_reduce function (#196)
+
+* Add map_reduce function
+
+* Note return type
+
+* keyfunc won't be None
+
+* Correct typo in docstring
+---
+ docs/api.rst                      |  1 +
+ more_itertools/more.py            | 68 +++++++++++++++++++++++++++++++
+ more_itertools/tests/test_more.py | 35 +++++++++++++++-
+ 3 files changed, 103 insertions(+), 1 deletion(-)
+
+diff --git a/docs/api.rst b/docs/api.rst
+index b1c0632..914e5bc 100644
+--- a/docs/api.rst
++++ b/docs/api.rst
+@@ -129,6 +129,7 @@ These tools return summarized or aggregated data from an iterable.
+ .. autofunction:: consecutive_groups(iterable, ordering=lambda x: x)
+ .. autofunction:: exactly_n(iterable, n, predicate=bool)
+ .. autoclass:: run_length
++.. autofunction:: map_reduce
+ 
+ ----
+ 
+diff --git a/more_itertools/more.py b/more_itertools/more.py
+index 21a1497..c4b08ae 100644
+--- a/more_itertools/more.py
++++ b/more_itertools/more.py
+@@ -51,6 +51,7 @@ __all__ = [
+     'locate',
+     'lstrip',
+     'make_decorator',
++    'map_reduce',
+     'numeric_range',
+     'one',
+     'padded',
+@@ -1983,3 +1984,70 @@ def make_decorator(wrapping_func, result_index=0):
+         return outer_wrapper
+ 
+     return decorator
++
++
++def map_reduce(iterable, keyfunc, valuefunc=None, reducefunc=None):
++    """Return a dictionary that maps the items in *iterable* to categories
++    defined by *keyfunc*, transforms them with *valuefunc*, and
++    then summarizes them by category with *reducefunc*.
++
++    *valuefunc* defaults to the identity function if it is unspecified.
++    If *reducefunc* is unspecified, no summarization takes place:
++
++        >>> keyfunc = lambda x: x.upper()
++        >>> result = map_reduce('abbccc', keyfunc)
++        >>> sorted(result.items())
++        [('A', ['a']), ('B', ['b', 'b']), ('C', ['c', 'c', 'c'])]
++
++    Specifying *valuefunc* transforms the categorized items:
++
++        >>> keyfunc = lambda x: x.upper()
++        >>> valuefunc = lambda x: 1
++        >>> result = map_reduce('abbccc', keyfunc, valuefunc)
++        >>> sorted(result.items())
++        [('A', [1]), ('B', [1, 1]), ('C', [1, 1, 1])]
++
++    Specifying *reducefunc* summarizes the categorized items:
++
++        >>> keyfunc = lambda x: x.upper()
++        >>> valuefunc = lambda x: 1
++        >>> reducefunc = sum
++        >>> result = map_reduce('abbccc', keyfunc, valuefunc, reducefunc)
++        >>> sorted(result.items())
++        [('A', 1), ('B', 2), ('C', 3)]
++
++    You may want to filter the input iterable before applying the map/reduce
++    proecdure:
++
++        >>> all_items = range(30)
++        >>> items = [x for x in all_items if 10 <= x <= 20]  # Filter
++        >>> keyfunc = lambda x: x % 2  # Evens map to 0; odds to 1
++        >>> categories = map_reduce(items, keyfunc=keyfunc)
++        >>> sorted(categories.items())
++        [(0, [10, 12, 14, 16, 18, 20]), (1, [11, 13, 15, 17, 19])]
++        >>> summaries = map_reduce(items, keyfunc=keyfunc, reducefunc=sum)
++        >>> sorted(summaries.items())
++        [(0, 90), (1, 75)]
++
++    Note that all items in the iterable are gathered into a list before the
++    summarization step, which may require significant storage.
++
++    The returned object is a :obj:`collections.defaultdict` with the
++    ``default_factory`` set to ``None``, such that it behaves like a normal
++    dictionary.
++
++    """
++    valuefunc = (lambda x: x) if (valuefunc is None) else valuefunc
++
++    ret = defaultdict(list)
++    for item in iterable:
++        key = keyfunc(item)
++        value = valuefunc(item)
++        ret[key].append(value)
++
++    if reducefunc is not None:
++        for key, value_list in ret.items():
++            ret[key] = reducefunc(value_list)
++
++    ret.default_factory = None
++    return ret
+diff --git a/more_itertools/tests/test_more.py b/more_itertools/tests/test_more.py
+index d8ada9c..0ac4abd 100644
+--- a/more_itertools/tests/test_more.py
++++ b/more_itertools/tests/test_more.py
+@@ -15,7 +15,7 @@ from itertools import (
+     product,
+     repeat,
+ )
+-from operator import add, itemgetter
++from operator import add, mul, itemgetter
+ from unittest import TestCase
+ 
+ from six.moves import filter, map, range, zip
+@@ -1792,3 +1792,36 @@ class MakeDecoratorTests(TestCase):
+ 
+         it.seek(0)
+         self.assertEqual(list(it), ['0', '1', '2', '3', '4'])
++
++
++class MapReduceTests(TestCase):
++    def test_default(self):
++        iterable = (str(x) for x in range(5))
++        keyfunc = lambda x: int(x) // 2
++        actual = sorted(mi.map_reduce(iterable, keyfunc).items())
++        expected = [(0, ['0', '1']), (1, ['2', '3']), (2, ['4'])]
++        self.assertEqual(actual, expected)
++
++    def test_valuefunc(self):
++        iterable = (str(x) for x in range(5))
++        keyfunc = lambda x: int(x) // 2
++        valuefunc = int
++        actual = sorted(mi.map_reduce(iterable, keyfunc, valuefunc).items())
++        expected = [(0, [0, 1]), (1, [2, 3]), (2, [4])]
++        self.assertEqual(actual, expected)
++
++    def test_reducefunc(self):
++        iterable = (str(x) for x in range(5))
++        keyfunc = lambda x: int(x) // 2
++        valuefunc = int
++        reducefunc = lambda value_list: reduce(mul, value_list, 1)
++        actual = sorted(
++            mi.map_reduce(iterable, keyfunc, valuefunc, reducefunc).items()
++        )
++        expected = [(0, 0), (1, 6), (2, 4)]
++        self.assertEqual(actual, expected)
++
++    def test_ret(self):
++        d = mi.map_reduce([1, 0, 2, 0, 1, 0], bool)
++        self.assertEqual(d, {False: [0, 0, 0], True: [1, 2, 1]})
++        self.assertRaises(KeyError, lambda: d[None].append(1))
+-- 
+2.39.0.windows.2
+

python-more-itertools.spec

@@ -1,6 +1,6 @@
 Name:           python-more-itertools
 Version:        4.1.0
-Release:        7
+Release:        8
 Summary:        An opensource python library wrapping around itertools
 License:        MIT
 URL:            https://github.com/erikrose/more-itertools
@@ -9,6 +9,7 @@ BuildArch:      noarch
 Patch0000:      python37.patch
 Patch0001:      0001-fix-for-python-3.7-deprecation-warning-about-importi.patch
 Patch0002:      0002-more.py-document-ilen.patch
+Patch0003:      0003-Add-map_reduce-function-196.patch
 
 %description
 This is a python library for efficient use of itertools utility, which also \
@@ -63,6 +64,9 @@ See https://pythonhosted.org/more-itertools/index.html for more information.
 %{python3_sitelib}/more_itertools-%{version}-py%{python3_version}.egg-info
 
 %changelog
+* Fri Dec 22 2023 zhangliangpengkun<zhangliangpengkun@xfusion.com> - 4.1.0-8
+- Add map_reduce function (#196)
+
 * Thu Nov 30 2023 zhangliangpengkun<zhangliangpengkun@xfusion.com> - 4.1.0-7
 - more.py: document ilen