diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst index 771310d00f4..75aa55e5f0e 100644 --- a/Doc/library/collections.rst +++ b/Doc/library/collections.rst @@ -388,8 +388,6 @@ Example:: __slots__ = () - _fields = ('x', 'y') - def __new__(cls, x, y): return tuple.__new__(cls, (x, y)) @@ -404,11 +402,15 @@ Example:: 'Return a new Point object replacing specified fields with new values' return Point(*map(kwds.get, ('x', 'y'), self)) + @property + def _fields(self): + return ('x', 'y') + x = property(itemgetter(0)) y = property(itemgetter(1)) >>> p = Point(11, y=22) # instantiate with positional or keyword arguments - >>> p[0] + p[1] # indexable like the regular tuple (11, 22) + >>> p[0] + p[1] # indexable like the plain tuple (11, 22) 33 >>> x, y = p # unpack like a regular tuple >>> x, y diff --git a/Lib/collections.py b/Lib/collections.py index be4d4fdc6f8..a43fdfa97a9 100644 --- a/Lib/collections.py +++ b/Lib/collections.py @@ -1,4 +1,9 @@ __all__ = ['deque', 'defaultdict', 'namedtuple'] +# For bootstrapping reasons, the collection ABCs are defined in _abcoll.py. +# They should however be considered an integral part of collections.py. +from _abcoll import * +import _abcoll +__all__ += _abcoll.__all__ from _collections import deque, defaultdict from operator import itemgetter as _itemgetter @@ -6,12 +11,6 @@ from itertools import izip as _izip from keyword import iskeyword as _iskeyword import sys as _sys -# For bootstrapping reasons, the collection ABCs are defined in _abcoll.py. -# They should however be considered an integral part of collections.py. -from _abcoll import * -import _abcoll -__all__ += _abcoll.__all__ - def namedtuple(typename, field_names, verbose=False): """Returns a new subclass of tuple with named fields. @@ -19,9 +18,9 @@ def namedtuple(typename, field_names, verbose=False): >>> Point.__doc__ # docstring for the new class 'Point(x, y)' >>> p = Point(11, y=22) # instantiate with positional args or keywords - >>> p[0] + p[1] # works just like the tuple (11, 22) + >>> p[0] + p[1] # indexable like a plain tuple: (11, 22) 33 - >>> x, y = p # unpacks just like a tuple + >>> x, y = p # unpack like a regular tuple >>> x, y (11, 22) >>> p.x + p.y # fields also accessable by name @@ -61,7 +60,6 @@ def namedtuple(typename, field_names, verbose=False): template = '''class %(typename)s(tuple): '%(typename)s(%(argtxt)s)' \n __slots__ = () \n - _fields = property(lambda self: %(field_names)r) \n def __new__(cls, %(argtxt)s): return tuple.__new__(cls, (%(argtxt)s)) \n def __repr__(self): @@ -71,7 +69,10 @@ def namedtuple(typename, field_names, verbose=False): return dict(zip(%(field_names)r, self)) \n def _replace(self, **kwds): 'Return a new %(typename)s object replacing specified fields with new values' - return %(typename)s(*map(kwds.get, %(field_names)r, self)) \n\n''' % locals() + return %(typename)s(*map(kwds.get, %(field_names)r, self)) \n + @property + def _fields(self): + return %(field_names)r \n\n''' % locals() for i, name in enumerate(field_names): template += ' %s = property(itemgetter(%d))\n' % (name, i) if verbose: diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py index d6cfe9b2067..73ae62ade5d 100644 --- a/Lib/test/test_collections.py +++ b/Lib/test/test_collections.py @@ -90,9 +90,36 @@ class TestNamedTuple(unittest.TestCase): def test_odd_sizes(self): Zero = namedtuple('Zero', '') self.assertEqual(Zero(), ()) + self.assertEqual(repr(Zero()), 'Zero()') + self.assertEqual(Zero()._asdict(), {}) + self.assertEqual(Zero()._fields, ()) + Dot = namedtuple('Dot', 'd') self.assertEqual(Dot(1), (1,)) + self.assertEqual(Dot(1).d, 1) + self.assertEqual(repr(Dot(1)), 'Dot(d=1)') + self.assertEqual(Dot(1)._asdict(), {'d':1}) + self.assertEqual(Dot(1)._replace(d=999), (999,)) + self.assertEqual(Dot(1)._fields, ('d',)) + n = 10000 + import string, random + names = [''.join([random.choice(string.letters) for j in range(10)]) for i in range(n)] + Big = namedtuple('Big', names) + b = Big(*range(n)) + self.assertEqual(b, tuple(range(n))) + for pos, name in enumerate(names): + self.assertEqual(getattr(b, name), pos) + repr(b) # make sure repr() doesn't blow-up + d = b._asdict() + d_expected = dict(zip(names, range(n))) + self.assertEqual(d, d_expected) + b2 = b._replace(**dict([(names[1], 999),(names[-5], 42)])) + b2_expected = range(n) + b2_expected[1] = 999 + b2_expected[-5] = 42 + self.assertEqual(b2, tuple(b2_expected)) + self.assertEqual(b._fields, tuple(names)) class TestOneTrickPonyABCs(unittest.TestCase):