[Python-checkins] r58186 - in python/trunk: Doc/library/collections.rst Lib/collections.py Lib/test/test_collections.py
raymond.hettinger
python-checkins at python.org
Tue Sep 18 05:33:19 CEST 2007
Author: raymond.hettinger
Date: Tue Sep 18 05:33:19 2007
New Revision: 58186
Modified:
python/trunk/Doc/library/collections.rst
python/trunk/Lib/collections.py
python/trunk/Lib/test/test_collections.py
Log:
Handle corner cased on 0-tuples and 1-tuples. Add verbose option so people can see how it works.
Modified: python/trunk/Doc/library/collections.rst
==============================================================================
--- python/trunk/Doc/library/collections.rst (original)
+++ python/trunk/Doc/library/collections.rst Tue Sep 18 05:33:19 2007
@@ -364,7 +364,7 @@
--------------------------------------------
-.. function:: NamedTuple(typename, fieldnames)
+.. function:: NamedTuple(typename, fieldnames, [verbose])
Returns a new tuple subclass named *typename*. The new subclass is used to
create tuple-like objects that have fields accessable by attribute lookup as
@@ -412,6 +412,23 @@
>>> print Color(*m.popitem())
Color(name='blue', code=3)
+ If *verbose* is true, the *NamedTuple* call will print the class definition::
+
+ >>> Point = NamedTuple('Point', 'x y', verbose=True)
+ class Point(tuple):
+ 'Point(x, y)'
+ __slots__ = ()
+ __fields__ = ('x', 'y')
+ def __new__(cls, x, y):
+ return tuple.__new__(cls, (x, y))
+ def __repr__(self):
+ return 'Point(x=%r, y=%r)' % self
+ def __replace__(self, field, value):
+ 'Return a new Point object replacing one field with a new value'
+ return Point(**dict(zip(('x', 'y'), self) + [(field, value)]))
+ x = property(itemgetter(0))
+ y = property(itemgetter(1))
+
In addition to the methods inherited from tuples, named tuples support
an additonal method and an informational read-only attribute.
Modified: python/trunk/Lib/collections.py
==============================================================================
--- python/trunk/Lib/collections.py (original)
+++ python/trunk/Lib/collections.py Tue Sep 18 05:33:19 2007
@@ -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))
Modified: python/trunk/Lib/test/test_collections.py
==============================================================================
--- python/trunk/Lib/test/test_collections.py (original)
+++ python/trunk/Lib/test/test_collections.py Tue Sep 18 05:33:19 2007
@@ -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]
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