Handle corner cased on 0-tuples and 1-tuples. Add verbose option so people can see how it works.
diff --git a/Lib/collections.py b/Lib/collections.py
index c2b1176..816f864 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -4,7 +4,7 @@
from operator import itemgetter as _itemgetter
import sys as _sys
-def NamedTuple(typename, s):
+def NamedTuple(typename, s, verbose=False):
"""Returns a new subclass of tuple with named fields.
>>> Point = NamedTuple('Point', 'x y')
@@ -28,25 +28,26 @@
"""
- field_names = tuple(s.replace(',', ' ').split()) # names separated by spaces and/or commas
+ field_names = tuple(s.replace(',', ' ').split()) # names separated by spaces and/or commas
if not ''.join((typename,) + field_names).replace('_', '').isalnum():
raise ValueError('Type names and field names can only contain alphanumeric characters and underscores')
- argtxt = ', '.join(field_names)
+ argtxt = repr(field_names).replace("'", "")[1:-1] # tuple repr without parens or quotes
reprtxt = ', '.join('%s=%%r' % name for name in field_names)
template = '''class %(typename)s(tuple):
'%(typename)s(%(argtxt)s)'
__slots__ = ()
__fields__ = %(field_names)r
def __new__(cls, %(argtxt)s):
- return tuple.__new__(cls, (%(argtxt)s,))
+ return tuple.__new__(cls, (%(argtxt)s))
def __repr__(self):
return '%(typename)s(%(reprtxt)s)' %% self
def __replace__(self, field, value):
'Return a new %(typename)s object replacing one field with a new value'
- return %(typename)s(**dict(zip(%(field_names)r, self) + [(field, value)]))
- ''' % locals()
+ return %(typename)s(**dict(zip(%(field_names)r, self) + [(field, value)])) \n''' % locals()
for i, name in enumerate(field_names):
- template += '\n %s = property(itemgetter(%d))\n' % (name, i)
+ template += ' %s = property(itemgetter(%d))\n' % (name, i)
+ if verbose:
+ print template
m = dict(itemgetter=_itemgetter)
exec template in m
result = m[typename]
@@ -62,7 +63,7 @@
if __name__ == '__main__':
# verify that instances can be pickled
from cPickle import loads, dumps
- Point = NamedTuple('Point', 'x, y')
+ Point = NamedTuple('Point', 'x, y', True)
p = Point(x=10, y=20)
assert p == loads(dumps(p))
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 94015b4..ab36ad8 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -58,6 +58,12 @@
self.assertRaises(AttributeError, eval, 'p.z', locals())
+ def test_odd_sizes(self):
+ Zero = NamedTuple('Zero', '')
+ self.assertEqual(Zero(), ())
+ Dot = NamedTuple('Dot', 'd')
+ self.assertEqual(Dot(1), (1,))
+
def test_main(verbose=None):
import collections as CollectionsModule
test_classes = [TestNamedTuple]