Merged revisions 59541-59561 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
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r59544 | raymond.hettinger | 2007-12-18 01:13:45 +0100 (Tue, 18 Dec 2007) | 1 line
Add more namedtuple() test cases. Neaten the code and comments.
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r59545 | christian.heimes | 2007-12-18 04:38:03 +0100 (Tue, 18 Dec 2007) | 3 lines
Fixed for #1601: IDLE not working correctly on Windows (Py30a2/IDLE30a1)
Amaury's ideas works great. Should we build the Python core with WINVER=0x0500 and _WIN32_WINNT=0x0500, too?
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r59546 | christian.heimes | 2007-12-18 10:00:13 +0100 (Tue, 18 Dec 2007) | 1 line
Make it a bit easier to test Tcl/Tk and idle from a build dir.
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r59547 | christian.heimes | 2007-12-18 10:12:10 +0100 (Tue, 18 Dec 2007) | 1 line
Removed several unused files from the PCbuild9 directory. They are relics from the past.
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r59548 | raymond.hettinger | 2007-12-18 19:26:18 +0100 (Tue, 18 Dec 2007) | 29 lines
Speed-up dictionary constructor by about 10%.
New opcode, STORE_MAP saves the compiler from awkward stack manipulations
and specializes for dicts using PyDict_SetItem instead of PyObject_SetItem.
Old disassembly:
0 BUILD_MAP 0
3 DUP_TOP
4 LOAD_CONST 1 (1)
7 ROT_TWO
8 LOAD_CONST 2 ('x')
11 STORE_SUBSCR
12 DUP_TOP
13 LOAD_CONST 3 (2)
16 ROT_TWO
17 LOAD_CONST 4 ('y')
20 STORE_SUBSCR
New disassembly:
0 BUILD_MAP 0
3 LOAD_CONST 1 (1)
6 LOAD_CONST 2 ('x')
9 STORE_MAP
10 LOAD_CONST 3 (2)
13 LOAD_CONST 4 ('y')
16 STORE_MAP
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r59549 | thomas.heller | 2007-12-18 20:00:34 +0100 (Tue, 18 Dec 2007) | 2 lines
Issue #1642: Fix segfault in ctypes when trying to delete attributes.
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r59551 | guido.van.rossum | 2007-12-18 21:10:42 +0100 (Tue, 18 Dec 2007) | 2 lines
Issue #1645 by Alberto Bertogli. Fix a comment.
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r59553 | raymond.hettinger | 2007-12-18 22:24:09 +0100 (Tue, 18 Dec 2007) | 12 lines
Give meaning to the oparg for BUILD_MAP: estimated size of the dictionary.
Allows dictionaries to be pre-sized (upto 255 elements) saving time lost
to re-sizes with their attendant mallocs and re-insertions.
Has zero effect on small dictionaries (5 elements or fewer), a slight
benefit for dicts upto 22 elements (because they had to resize once
anyway), and more benefit for dicts upto 255 elements (saving multiple
resizes during the build-up and reducing the number of collisions on
the first insertions). Beyond 255 elements, there is no addional benefit.
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r59554 | christian.heimes | 2007-12-18 22:56:09 +0100 (Tue, 18 Dec 2007) | 1 line
Fixed #1649: IDLE error: dictionary changed size during iteration
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r59557 | raymond.hettinger | 2007-12-18 23:21:27 +0100 (Tue, 18 Dec 2007) | 1 line
Simplify and speedup _asdict() for named tuples.
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r59558 | christian.heimes | 2007-12-19 00:22:54 +0100 (Wed, 19 Dec 2007) | 3 lines
Applied patch #1635: Float patch for inf and nan on Windows (and other platforms).
The patch unifies float("inf") and repr(float("inf")) on all platforms.
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r59559 | raymond.hettinger | 2007-12-19 00:51:15 +0100 (Wed, 19 Dec 2007) | 1 line
Users demand iterable input for named tuples. The author capitulates.
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r59560 | raymond.hettinger | 2007-12-19 01:21:06 +0100 (Wed, 19 Dec 2007) | 1 line
Beef-up tests for dict literals
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r59561 | raymond.hettinger | 2007-12-19 01:27:21 +0100 (Wed, 19 Dec 2007) | 1 line
Zap a duplicate line
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diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst
index 1982187..e01c52e 100644
--- a/Doc/library/collections.rst
+++ b/Doc/library/collections.rst
@@ -421,27 +421,31 @@
__slots__ = ()
- _fields = ('x', 'y')
-
def __new__(cls, x, y):
return tuple.__new__(cls, (x, y))
+ _cast = classmethod(tuple.__new__)
+
def __repr__(self):
return 'Point(x=%r, y=%r)' % self
- def _asdict(self):
+ def _asdict(t):
'Return a new dict which maps field names to their values'
- return dict(zip(('x', 'y'), self))
+ return {'x': t[0], 'y': t[1]}
def _replace(self, **kwds):
'Return a new Point object replacing specified fields with new values'
- return Point(*map(kwds.get, ('x', 'y'), self))
+ return Point._cast(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
@@ -456,34 +460,31 @@
EmployeeRecord = namedtuple('EmployeeRecord', 'name, age, title, department, paygrade')
- from itertools import starmap
import csv
- for record in starmap(EmployeeRecord, csv.reader(open("employees.csv", "rb"))):
+ for emp in map(EmployeeRecord._cast, csv.reader(open("employees.csv", "rb"))):
print(emp.name, emp.title)
import sqlite3
conn = sqlite3.connect('/companydata')
cursor = conn.cursor()
cursor.execute('SELECT name, age, title, department, paygrade FROM employees')
- for emp in starmap(EmployeeRecord, cursor.fetchall()):
+ for emp in map(EmployeeRecord._cast, cursor.fetchall()):
print emp.name, emp.title
-When casting a single record to a named tuple, use the star-operator [#]_ to unpack
-the values::
+In addition to the methods inherited from tuples, named tuples support
+three additonal methods and a read-only attribute.
+
+.. method:: namedtuple._cast(iterable)
+
+ Class method returning a new instance taking the positional arguments from the *iterable*.
+ Useful for casting existing sequences and iterables to named tuples:
+
+::
>>> t = [11, 22]
- >>> Point(*t) # the star-operator unpacks any iterable object
+ >>> Point._cast(t)
Point(x=11, y=22)
-When casting a dictionary to a named tuple, use the double-star-operator::
-
- >>> d = {'x': 11, 'y': 22}
- >>> Point(**d)
- Point(x=11, y=22)
-
-In addition to the methods inherited from tuples, named tuples support
-two additonal methods and a read-only attribute.
-
.. method:: somenamedtuple._asdict()
Return a new dict which maps field names to their corresponding values:
@@ -529,6 +530,12 @@
>>> getattr(p, 'x')
11
+When casting a dictionary to a named tuple, use the double-star-operator [#]_::
+
+ >>> d = {'x': 11, 'y': 22}
+ >>> Point(**d)
+ Point(x=11, y=22)
+
Since a named tuple is a regular Python class, it is easy to add or change
functionality. For example, the display format can be changed by overriding
the :meth:`__repr__` method:
@@ -551,5 +558,5 @@
.. rubric:: Footnotes
-.. [#] For information on the star-operator see
+.. [#] For information on the double-star-operator see
:ref:`tut-unpacking-arguments` and :ref:`calls`.