Accept Issac Morland's suggestion for __replace__ to allow multiple replacements
(suprisingly, this simplifies the signature, improves clarity, and is comparably fast).
Update the docs to reflect a previous change to the function name.
Add an example to the docs showing how to override the default __repr__ method.
diff --git a/Lib/collections.py b/Lib/collections.py
index 40f5187..6b2e58d 100644
--- a/Lib/collections.py
+++ b/Lib/collections.py
@@ -24,7 +24,7 @@
11
>>> Point(**d) # convert from a dictionary
Point(x=11, y=22)
- >>> p.__replace__('x', 100) # __replace__() is like str.replace() but targets a named field
+ >>> p.__replace__(x=100) # __replace__() is like str.replace() but targets named fields
Point(x=100, y=22)
"""
@@ -62,9 +62,9 @@
def __asdict__(self, dict=dict, zip=zip):
'Return a new dict mapping field names to their values'
return dict(zip(%(field_names)r, self))
- def __replace__(self, field, value, dict=dict, zip=zip):
- 'Return a new %(typename)s object replacing one field with a new value'
- return %(typename)s(**dict(zip(%(field_names)r, self) + [(field, value)])) \n''' % locals()
+ def __replace__(self, **kwds):
+ 'Return a new %(typename)s object replacing specified fields with new values'
+ return %(typename)s(**dict(self.__asdict__().items() + kwds.items())) \n''' % locals()
for i, name in enumerate(field_names):
template += ' %s = property(itemgetter(%d))\n' % (name, i)
if verbose:
@@ -98,6 +98,10 @@
p = Point(x=10, y=20)
assert p == loads(dumps(p))
+ # test and demonstrate ability to override methods
+ Point.__repr__ = lambda self: 'Point(%.3f, %.3f)' % self
+ print p
+
import doctest
TestResults = namedtuple('TestResults', 'failed attempted')
print TestResults(*doctest.testmod())