Fix field name conflicts for named tuples.

This commit is contained in:
Raymond Hettinger 2009-05-27 02:17:26 +00:00
parent 9c270c0362
commit 4f1e16338d
4 changed files with 56 additions and 12 deletions

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@ -524,8 +524,8 @@ Example:
<BLANKLINE>
_fields = ('x', 'y')
<BLANKLINE>
def __new__(cls, x, y):
return tuple.__new__(cls, (x, y))
def __new__(_cls, x, y):
return _tuple.__new__(_cls, (x, y))
<BLANKLINE>
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
@ -542,9 +542,9 @@ Example:
'Return a new dict which maps field names to their values'
return {'x': t[0], 'y': t[1]}
<BLANKLINE>
def _replace(self, **kwds):
def _replace(_self, **kwds):
'Return a new Point object replacing specified fields with new values'
result = self._make(map(kwds.pop, ('x', 'y'), self))
result = _self._make(map(kwds.pop, ('x', 'y'), _self))
if kwds:
raise ValueError('Got unexpected field names: %r' % kwds.keys())
return result
@ -552,8 +552,8 @@ Example:
def __getnewargs__(self):
return tuple(self)
<BLANKLINE>
x = property(itemgetter(0))
y = property(itemgetter(1))
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 plain tuple (11, 22)

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@ -63,8 +63,8 @@ def namedtuple(typename, field_names, verbose=False):
'%(typename)s(%(argtxt)s)' \n
__slots__ = () \n
_fields = %(field_names)r \n
def __new__(cls, %(argtxt)s):
return tuple.__new__(cls, (%(argtxt)s)) \n
def __new__(_cls, %(argtxt)s):
return _tuple.__new__(_cls, (%(argtxt)s)) \n
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
'Make a new %(typename)s object from a sequence or iterable'
@ -77,22 +77,23 @@ def namedtuple(typename, field_names, verbose=False):
def _asdict(t):
'Return a new dict which maps field names to their values'
return {%(dicttxt)s} \n
def _replace(self, **kwds):
def _replace(_self, **kwds):
'Return a new %(typename)s object replacing specified fields with new values'
result = self._make(map(kwds.pop, %(field_names)r, self))
result = _self._make(map(kwds.pop, %(field_names)r, _self))
if kwds:
raise ValueError('Got unexpected field names: %%r' %% kwds.keys())
return result \n
def __getnewargs__(self):
return tuple(self) \n\n''' % locals()
for i, name in enumerate(field_names):
template += ' %s = property(itemgetter(%d))\n' % (name, i)
template += ' %s = _property(_itemgetter(%d))\n' % (name, i)
if verbose:
print template
# Execute the template string in a temporary namespace and
# support tracing utilities by setting a value for frame.f_globals['__name__']
namespace = dict(itemgetter=_itemgetter, __name__='namedtuple_%s' % typename)
namespace = dict(_itemgetter=_itemgetter, __name__='namedtuple_%s' % typename,
_property=property, _tuple=tuple)
try:
exec template in namespace
except SyntaxError, e:

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@ -2,6 +2,8 @@ import unittest, doctest
from test import test_support
from collections import namedtuple
import pickle, cPickle, copy
import keyword
import re
from collections import Hashable, Iterable, Iterator
from collections import Sized, Container, Callable
from collections import Set, MutableSet
@ -154,6 +156,44 @@ class TestNamedTuple(unittest.TestCase):
self.assertEqual(p, q)
self.assertEqual(p._fields, q._fields)
def test_name_conflicts(self):
# Some names like "self", "cls", "tuple", "itemgetter", and "property"
# failed when used as field names. Test to make sure these now work.
T = namedtuple('T', 'itemgetter property self cls tuple')
t = T(1, 2, 3, 4, 5)
self.assertEqual(t, (1,2,3,4,5))
newt = t._replace(itemgetter=10, property=20, self=30, cls=40, tuple=50)
self.assertEqual(newt, (10,20,30,40,50))
# Broader test of all interesting names in a template
with test_support.captured_stdout() as template:
T = namedtuple('T', 'x', verbose=True)
words = set(re.findall('[A-Za-z]+', template.getvalue()))
words -= set(keyword.kwlist)
T = namedtuple('T', words)
# test __new__
values = tuple(range(len(words)))
t = T(*values)
self.assertEqual(t, values)
t = T(**dict(zip(T._fields, values)))
self.assertEqual(t, values)
# test _make
t = T._make(values)
self.assertEqual(t, values)
# exercise __repr__
repr(t)
# test _asdict
self.assertEqual(t._asdict(), dict(zip(T._fields, values)))
# test _replace
t = T._make(values)
newvalues = tuple(v*10 for v in values)
newt = t._replace(**dict(zip(T._fields, newvalues)))
self.assertEqual(newt, newvalues)
# test _fields
self.assertEqual(T._fields, tuple(words))
# test __getnewargs__
self.assertEqual(t.__getnewargs__(), values)
class ABCTestCase(unittest.TestCase):
def validate_abstract_methods(self, abc, *names):

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@ -53,6 +53,9 @@ Library
- Issue #6050: Don't fail extracting a directory from a zipfile if
the directory already exists.
- collections.namedtuple() was not working with the following field
names: cls, self, tuple, itemgetter, and property.
- Issue #1309352: fcntl now converts its third arguments to a C `long` rather
than an int, which makes some operations possible under 64-bit Linux (e.g.
DN_MULTISHOT with F_NOTIFY).