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Minor named tuple clean-ups.

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This commit is contained in:
Raymond Hettinger 2011-03-22 22:36:21 -07:00
parent fef854602b
commit b2d0945c87
2 changed files with 42 additions and 42 deletions
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65
Doc/library/collections.rst
View file

@ -711,47 +711,48 @@ they add the ability to access fields by name instead of position index.
>>> p = Point(x=10, y=11)
>>> # Example using the verbose option to print the class definition
>>> Point = namedtuple('Point', 'x y', verbose=True)
>>> Point = namedtuple('Point', ['x', 'y'], verbose=True)
class Point(tuple):
'Point(x, y)'
'Point(x, y)'
<BLANKLINE>
__slots__ = ()
__slots__ = ()
<BLANKLINE>
_fields = ('x', 'y')
_fields = ('x', 'y')
<BLANKLINE>
def __new__(_cls, x, y):
'Create a new instance of Point(x, y)'
return _tuple.__new__(_cls, (x, y))
def __new__(_cls, x, y):
'Create a new instance of Point(x, y)'
return _tuple.__new__(_cls, (x, y))
<BLANKLINE>
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
'Make a new Point object from a sequence or iterable'
result = new(cls, iterable)
if len(result) != 2:
raise TypeError('Expected 2 arguments, got %d' % len(result))
return result
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
'Make a new Point object from a sequence or iterable'
result = new(cls, iterable)
if len(result) != 2:
raise TypeError('Expected 2 arguments, got %d' % len(result))
return result
<BLANKLINE>
def __repr__(self):
'Return a nicely formatted representation string'
return self.__class__.__name__ + '(x=%r, y=%r)' % self
def __repr__(self):
'Return a nicely formatted representation string'
return self.__class__.__name__ + '(x=%r, y=%r)' % self
<BLANKLINE>
def _asdict(self):
'Return a new OrderedDict which maps field names to their values'
return OrderedDict(zip(self._fields, self))
def _asdict(self):
'Return a new OrderedDict which maps field names to their values'
return OrderedDict(zip(self._fields, self))
<BLANKLINE>
def _replace(_self, **kwds):
'Return a new Point object replacing specified fields with new values'
result = _self._make(map(kwds.pop, ('x', 'y'), _self))
if kwds:
raise ValueError('Got unexpected field names: %r' % list(kwds.keys()))
return result
def _replace(_self, **kwds):
'Return a new Point object replacing specified fields with new values'
result = _self._make(map(kwds.pop, ('x', 'y'), _self))
if kwds:
raise ValueError('Got unexpected field names: %r' % list(kwds))
return result
<BLANKLINE>
def __getnewargs__(self):
'Return self as a plain tuple. Used by copy and pickle.'
return tuple(self)
def __getnewargs__(self):
'Return self as a plain tuple. Used by copy and pickle.'
return tuple(self)
<BLANKLINE>
x = _property(_itemgetter(0), doc='Alias for field number 0')
y = _property(_itemgetter(1), doc='Alias for field number 1')
x = _property(_itemgetter(0), doc='Alias for field number 0')
<BLANKLINE>
y = _property(_itemgetter(1), doc='Alias for field number 1')
>>> p = Point(11, y=22) # instantiate with positional or keyword arguments
>>> p[0] + p[1] # indexable like the plain tuple (11, 22)
@ -867,7 +868,6 @@ a fixed-width print format:
The subclass shown above sets ``__slots__`` to an empty tuple. This helps
keep memory requirements low by preventing the creation of instance dictionaries.
Subclassing is not useful for adding new, stored fields. Instead, simply
create a new named tuple type from the :attr:`_fields` attribute:
@ -879,6 +879,7 @@ customize a prototype instance:
>>> Account = namedtuple('Account', 'owner balance transaction_count')
>>> default_account = Account('<owner name>', 0.0, 0)
>>> johns_account = default_account._replace(owner='John')
>>> janes_account = default_account._replace(owner='Jane')
Enumerated constants can be implemented with named tuples, but it is simpler
and more efficient to use a simple class declaration:

19
Lib/collections/__init__.py
View file

@ -265,7 +265,7 @@ class {typename}(tuple):
'Return a new {typename} object replacing specified fields with new values'
result = _self._make(map(kwds.pop, {field_names!r}, _self))
if kwds:
raise ValueError('Got unexpected field names: %r' % kwds.keys())
raise ValueError('Got unexpected field names: %r' % list(kwds))
return result
def __getnewargs__(self):
@ -309,18 +309,17 @@ def namedtuple(typename, field_names, verbose=False, rename=False):
# generating informative error messages and preventing template injection attacks.
if isinstance(field_names, str):
field_names = field_names.replace(',', ' ').split() # names separated by whitespace and/or commas
field_names = tuple(map(str, field_names))
field_names = list(map(str, field_names))
if rename:
names = list(field_names)
seen = set()
for i, name in enumerate(names):
if (not all(c.isalnum() or c=='_' for c in name) or _iskeyword(name)
for index, name in enumerate(field_names):
if (not all(c.isalnum() or c=='_' for c in name)
or _iskeyword(name)
or not name or name[0].isdigit() or name.startswith('_')
or name in seen):
names[i] = '_%d' % i
field_names[index] = '_%d' % index
seen.add(name)
field_names = tuple(names)
for name in (typename,) + field_names:
for name in [typename] + field_names:
if not all(c.isalnum() or c=='_' for c in name):
raise ValueError('Type names and field names can only contain alphanumeric characters and underscores: %r' % name)
if _iskeyword(name):
@ -338,9 +337,9 @@ def namedtuple(typename, field_names, verbose=False, rename=False):
# Fill-in the class template
class_definition = _class_template.format(
typename = typename,
field_names = field_names,
field_names = tuple(field_names),
num_fields = len(field_names),
arg_list = repr(field_names).replace("'", "")[1:-1],
arg_list = repr(tuple(field_names)).replace("'", "")[1:-1],
repr_fmt = ', '.join(_repr_template.format(name=name) for name in field_names),
field_defs = '\n'.join(_field_template.format(index=index, name=name)
for index, name in enumerate(field_names))