Cleaner method naming convention

This commit is contained in:
Raymond Hettinger 2007-12-14 02:49:47 +00:00
parent 90e10e79ea
commit 42da874cdd
3 changed files with 30 additions and 30 deletions

View file

@ -368,8 +368,8 @@ they add the ability to access fields by name instead of position index.
can be specified as a list of strings (such as ['x', 'y']).
Any valid Python identifier may be used for a fieldname except for names
starting and ending with double underscores. Valid identifiers consist of
letters, digits, and underscores but do not start with a digit and cannot be
starting with an underscore. Valid identifiers consist of letters, digits,
and underscores but do not start with a digit or underscore and cannot be
a :mod:`keyword` such as *class*, *for*, *return*, *global*, *pass*, *print*,
or *raise*.
@ -386,15 +386,15 @@ Example::
class Point(tuple):
'Point(x, y)'
__slots__ = ()
__fields__ = ('x', 'y')
_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 __asdict__(self):
def _asdict(self):
'Return a new dict mapping field names to their values'
return dict(zip(('x', 'y'), self))
def __replace__(self, **kwds):
def _replace(self, **kwds):
'Return a new Point object replacing specified fields with new values'
return Point(**dict(zip(('x', 'y'), self), **kwds))
x = property(itemgetter(0))
@ -444,40 +444,40 @@ When casting a dictionary to a named tuple, use the double-star-operator::
In addition to the methods inherited from tuples, named tuples support
two additonal methods and a read-only attribute.
.. method:: somenamedtuple.__asdict__()
.. method:: somenamedtuple._asdict()
Return a new dict which maps field names to their corresponding values:
::
>>> p.__asdict__()
>>> p._asdict()
{'x': 11, 'y': 22}
.. method:: somenamedtuple.__replace__(kwargs)
.. method:: somenamedtuple._replace(kwargs)
Return a new instance of the named tuple replacing specified fields with new values:
::
>>> p = Point(x=11, y=22)
>>> p.__replace__(x=33)
>>> p._replace(x=33)
Point(x=33, y=22)
>>> for partnum, record in inventory.items():
... inventory[partnum] = record.__replace__(price=newprices[partnum], updated=time.now())
... inventory[partnum] = record._replace(price=newprices[partnum], updated=time.now())
.. attribute:: somenamedtuple.__fields__
.. attribute:: somenamedtuple._fields
Return a tuple of strings listing the field names. This is useful for introspection
and for creating new named tuple types from existing named tuples.
::
>>> p.__fields__ # view the field names
>>> p._fields # view the field names
('x', 'y')
>>> Color = namedtuple('Color', 'red green blue')
>>> Pixel = namedtuple('Pixel', Point.__fields__ + Color.__fields__)
>>> Pixel = namedtuple('Pixel', Point._fields + Color._fields)
>>> Pixel(11, 22, 128, 255, 0)
Pixel(x=11, y=22, red=128, green=255, blue=0)'
@ -493,13 +493,13 @@ the :meth:`__repr__` method:
Point(10.000, 20.000)
Default values can be implemented by starting with a prototype instance
and customizing it with :meth:`__replace__`:
and customizing it with :meth:`_replace`:
::
>>> Account = namedtuple('Account', 'owner balance transaction_count')
>>> model_account = Account('<owner name>', 0.0, 0)
>>> johns_account = model_account.__replace__(owner='John')
>>> johns_account = model_account._replace(owner='John')
.. rubric:: Footnotes