Fixed #27126 -- Made {% regroup %} return a namedtuple to ease unpacking.
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@ -4,6 +4,7 @@ from __future__ import unicode_literals
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import re
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import sys
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import warnings
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from collections import namedtuple
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from datetime import datetime
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from itertools import cycle as itertools_cycle, groupby
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@ -335,6 +336,9 @@ class LoremNode(Node):
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return '\n\n'.join(paras)
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GroupedResult = namedtuple('GroupedResult', ['grouper', 'list'])
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class RegroupNode(Node):
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def __init__(self, target, expression, var_name):
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self.target, self.expression = target, expression
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@ -355,7 +359,7 @@ class RegroupNode(Node):
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# List of dictionaries in the format:
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# {'grouper': 'key', 'list': [list of contents]}.
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context[self.var_name] = [
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{'grouper': key, 'list': list(val)}
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GroupedResult(grouper=key, list=list(val))
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for key, val in
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groupby(obj_list, lambda obj: self.resolve_expression(obj, context))
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]
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@ -896,13 +896,36 @@ resulting list. Here, we're regrouping the ``cities`` list by the ``country``
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attribute and calling the result ``country_list``.
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``{% regroup %}`` produces a list (in this case, ``country_list``) of
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**group objects**. Each group object has two attributes:
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**group objects**. Group objects are instances of
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:py:func:`~collections.namedtuple` with two fields:
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* ``grouper`` -- the item that was grouped by (e.g., the string "India" or
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"Japan").
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* ``list`` -- a list of all items in this group (e.g., a list of all cities
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with country='India').
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.. versionchanged:: 1.11
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The group object was changed from a dictionary to a
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:py:func:`~collections.namedtuple`.
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Because ``{% regroup %}`` produces :py:func:`~collections.namedtuple` objects,
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you can also write the previous example as::
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{% regroup cities by country as country_list %}
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<ul>
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{% for country, local_cities in country_list %}
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<li>{{ country }}
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<ul>
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{% for city in local_cities %}
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<li>{{ city.name }}: {{ city.population }}</li>
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{% endfor %}
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</ul>
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</li>
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{% endfor %}
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</ul>
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Note that ``{% regroup %}`` does not order its input! Our example relies on
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the fact that the ``cities`` list was ordered by ``country`` in the first place.
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If the ``cities`` list did *not* order its members by ``country``, the
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@ -300,6 +300,10 @@ Templates
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supports context processors by setting the ``'context_processors'`` option in
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:setting:`OPTIONS <TEMPLATES-OPTIONS>`.
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* The :ttag:`regroup` tag now returns ``namedtuple``\s instead of dictionaries
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so you can unpack the group object directly in a loop, e.g.
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``{% for grouper, list in regrouped %}``.
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Tests
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~~~~~
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@ -100,3 +100,22 @@ class RegroupTagTests(SimpleTestCase):
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def test_regroup08(self):
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with self.assertRaises(TemplateSyntaxError):
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self.engine.get_template('regroup08')
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@setup({'regroup_unpack': '{% regroup data by bar as grouped %}'
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'{% for grouper, group in grouped %}'
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'{{ grouper }}:'
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'{% for item in group %}'
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'{{ item.foo }}'
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'{% endfor %},'
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'{% endfor %}'})
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def test_regroup_unpack(self):
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output = self.engine.render_to_string('regroup_unpack', {
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'data': [
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{'foo': 'c', 'bar': 1},
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{'foo': 'd', 'bar': 1},
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{'foo': 'a', 'bar': 2},
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{'foo': 'b', 'bar': 2},
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{'foo': 'x', 'bar': 3},
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],
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})
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self.assertEqual(output, '1:cd,2:ab,3:x,')
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