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Merged revisions 59541-59561 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk ........ 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. ........ 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? ........ 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. ........ 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. ........ 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 ........ 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. ........ 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. ........ 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. ........ 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 ........ r59557 | raymond.hettinger | 2007-12-18 23:21:27 +0100 (Tue, 18 Dec 2007) | 1 line Simplify and speedup _asdict() for named tuples. ........ 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. ........ 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. ........ r59560 | raymond.hettinger | 2007-12-19 01:21:06 +0100 (Wed, 19 Dec 2007) | 1 line Beef-up tests for dict literals ........ r59561 | raymond.hettinger | 2007-12-19 01:27:21 +0100 (Wed, 19 Dec 2007) | 1 line Zap a duplicate line ........
This commit is contained in:
Christian Heimes
parent
2c18161606
commit
99170a5dbf
42 changed files with 628 additions and 4149 deletions
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@ -421,27 +421,31 @@ Example::
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__slots__ = ()
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_fields = ('x', 'y')
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def __new__(cls, x, y):
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return tuple.__new__(cls, (x, y))
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_cast = classmethod(tuple.__new__)
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def __repr__(self):
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return 'Point(x=%r, y=%r)' % self
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def _asdict(self):
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def _asdict(t):
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'Return a new dict which maps field names to their values'
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return dict(zip(('x', 'y'), self))
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return {'x': t[0], 'y': t[1]}
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def _replace(self, **kwds):
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'Return a new Point object replacing specified fields with new values'
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return Point(*map(kwds.get, ('x', 'y'), self))
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return Point._cast(map(kwds.get, ('x', 'y'), self))
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@property
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def _fields(self):
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return ('x', 'y')
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x = property(itemgetter(0))
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y = property(itemgetter(1))
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>>> p = Point(11, y=22) # instantiate with positional or keyword arguments
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>>> p[0] + p[1] # indexable like the regular tuple (11, 22)
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>>> p[0] + p[1] # indexable like the plain tuple (11, 22)
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33
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>>> x, y = p # unpack like a regular tuple
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>>> x, y
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@ -456,34 +460,31 @@ by the :mod:`csv` or :mod:`sqlite3` modules::
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EmployeeRecord = namedtuple('EmployeeRecord', 'name, age, title, department, paygrade')
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from itertools import starmap
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import csv
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for record in starmap(EmployeeRecord, csv.reader(open("employees.csv", "rb"))):
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for emp in map(EmployeeRecord._cast, csv.reader(open("employees.csv", "rb"))):
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print(emp.name, emp.title)
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import sqlite3
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conn = sqlite3.connect('/companydata')
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cursor = conn.cursor()
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cursor.execute('SELECT name, age, title, department, paygrade FROM employees')
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for emp in starmap(EmployeeRecord, cursor.fetchall()):
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for emp in map(EmployeeRecord._cast, cursor.fetchall()):
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print emp.name, emp.title
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When casting a single record to a named tuple, use the star-operator [#]_ to unpack
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the values::
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In addition to the methods inherited from tuples, named tuples support
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three additonal methods and a read-only attribute.
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.. method:: namedtuple._cast(iterable)
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Class method returning a new instance taking the positional arguments from the *iterable*.
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Useful for casting existing sequences and iterables to named tuples:
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::
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>>> t = [11, 22]
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>>> Point(*t) # the star-operator unpacks any iterable object
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>>> Point._cast(t)
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Point(x=11, y=22)
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When casting a dictionary to a named tuple, use the double-star-operator::
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>>> d = {'x': 11, 'y': 22}
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>>> Point(**d)
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Point(x=11, y=22)
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In addition to the methods inherited from tuples, named tuples support
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two additonal methods and a read-only attribute.
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.. method:: somenamedtuple._asdict()
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Return a new dict which maps field names to their corresponding values:
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@ -529,6 +530,12 @@ function:
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>>> getattr(p, 'x')
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11
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When casting a dictionary to a named tuple, use the double-star-operator [#]_::
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>>> d = {'x': 11, 'y': 22}
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>>> Point(**d)
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Point(x=11, y=22)
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Since a named tuple is a regular Python class, it is easy to add or change
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functionality. For example, the display format can be changed by overriding
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the :meth:`__repr__` method:
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@ -551,5 +558,5 @@ and customizing it with :meth:`_replace`:
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.. rubric:: Footnotes
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.. [#] For information on the star-operator see
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.. [#] For information on the double-star-operator see
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:ref:`tut-unpacking-arguments` and :ref:`calls`.
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@ -435,7 +435,8 @@ available. They are listed here in alphabetical order.
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Convert a string or a number to floating point. If the argument is a string, it
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must contain a possibly signed decimal or floating point number, possibly
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embedded in whitespace. Otherwise, the argument may be an integer
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embedded in whitespace. The argument may also be [+|-]nan or [+|-]inf.
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Otherwise, the argument may be a plain integer
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or a floating point number, and a floating point number with the same value
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(within Python's floating point precision) is returned. If no argument is
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given, returns ``0.0``.
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@ -447,9 +448,10 @@ available. They are listed here in alphabetical order.
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single: Infinity
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When passing in a string, values for NaN and Infinity may be returned, depending
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on the underlying C library. The specific set of strings accepted which cause
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these values to be returned depends entirely on the C library and is known to
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vary.
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on the underlying C library. Float accepts the strings nan, inf and -inf for
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NaN and positive or negative infinity. The case and a leading + are ignored as
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well as a leading - is ignored for NaN. Float always represents NaN and infinity
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as nan, inf or -inf.
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The float type is described in :ref:`typesnumeric`.
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@ -285,7 +285,7 @@ numeric operations have a higher priority than comparison operations):
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+---------------------+---------------------------------+-------+--------------------+
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| ``int(x)`` | *x* converted to integer | \(3) | :func:`int` |
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+---------------------+---------------------------------+-------+--------------------+
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| ``float(x)`` | *x* converted to floating point | | :func:`float` |
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| ``float(x)`` | *x* converted to floating point | \(6) | :func:`float` |
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+---------------------+---------------------------------+-------+--------------------+
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| ``complex(re, im)`` | a complex number with real part | | :func:`complex` |
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| | *re*, imaginary part *im*. | | |
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@ -329,6 +329,13 @@ Notes:
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as in C; see functions :func:`floor` and :func:`ceil` in the :mod:`math` module
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for well-defined conversions.
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(6)
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float also accepts the strings "nan" and "inf" with an optional prefix "+"
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or "-" for Not a Number (NaN) and positive or negative infinity.
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.. versionadded:: 2.6
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.. % XXXJH exceptions: overflow (when? what operations?) zerodivision
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