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Code cleanups

This commit is contained in:
Raymond Hettinger 2012-06-08 13:24:12 -07:00
parent 1eda5c9a83
commit 491f7070f1
2 changed files with 105 additions and 76 deletions
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2
Doc/library/collections.rst
View File

@ -641,7 +641,9 @@ Example:
return tuple(self)
<BLANKLINE>
x = _property(_itemgetter(0), doc='Alias for field number 0')
<BLANKLINE>
y = _property(_itemgetter(1), doc='Alias for field number 1')
<BLANKLINE>
>>> p = Point(11, y=22) # instantiate with positional or keyword arguments
>>> p[0] + p[1] # indexable like the plain tuple (11, 22)

117
Lib/collections.py
View File

@ -234,10 +234,60 @@ class OrderedDict(dict):
### namedtuple
################################################################################
_class_template = '''\
class {typename}(tuple):
'{typename}({arg_list})'
__slots__ = ()
_fields = {field_names!r}
def __new__(_cls, {arg_list}):
'Create new instance of {typename}({arg_list})'
return _tuple.__new__(_cls, ({arg_list}))
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
'Make a new {typename} object from a sequence or iterable'
result = new(cls, iterable)
if len(result) != {num_fields:d}:
raise TypeError('Expected {num_fields:d} arguments, got %d' % len(result))
return result
def __repr__(self):
'Return a nicely formatted representation string'
return '{typename}({repr_fmt})' % self
def _asdict(self):
'Return a new OrderedDict which maps field names to their values'
return OrderedDict(zip(self._fields, self))
__dict__ = property(_asdict)
def _replace(_self, **kwds):
'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())
return result
def __getnewargs__(self):
'Return self as a plain tuple. Used by copy and pickle.'
return tuple(self)
{field_defs}
'''
_repr_template = '{name}=%r'
_field_template = '''\
{name} = _property(_itemgetter({index:d}), doc='Alias for field number {index:d}')
'''
def namedtuple(typename, field_names, verbose=False, rename=False):
"""Returns a new subclass of tuple with named fields.
>>> Point = namedtuple('Point', 'x y')
>>> Point = namedtuple('Point', ['x', 'y'])
>>> Point.__doc__ # docstring for the new class
'Point(x, y)'
>>> p = Point(11, y=22) # instantiate with positional args or keywords
@ -267,8 +317,11 @@ def namedtuple(typename, field_names, verbose=False, rename=False):
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)
or not name or name[0].isdigit() or name.startswith('_')
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
seen.add(name)
@ -280,60 +333,34 @@ def namedtuple(typename, field_names, verbose=False, rename=False):
raise ValueError('Type names and field names cannot be a keyword: %r' % name)
if name[0].isdigit():
raise ValueError('Type names and field names cannot start with a number: %r' % name)
seen_names = set()
seen = set()
for name in field_names:
if name.startswith('_') and not rename:
raise ValueError('Field names cannot start with an underscore: %r' % name)
if name in seen_names:
if name in seen:
raise ValueError('Encountered duplicate field name: %r' % name)
seen_names.add(name)
seen.add(name)
# Create and fill-in the class template
numfields = len(field_names)
argtxt = repr(field_names).replace("'", "")[1:-1] # tuple repr without parens or quotes
reprtxt = ', '.join('%s=%%r' % name for name in field_names)
template = '''class %(typename)s(tuple):
'%(typename)s(%(argtxt)s)' \n
__slots__ = () \n
_fields = %(field_names)r \n
def __new__(_cls, %(argtxt)s):
'Create new instance of %(typename)s(%(argtxt)s)'
return _tuple.__new__(_cls, (%(argtxt)s)) \n
@classmethod
def _make(cls, iterable, new=tuple.__new__, len=len):
'Make a new %(typename)s object from a sequence or iterable'
result = new(cls, iterable)
if len(result) != %(numfields)d:
raise TypeError('Expected %(numfields)d arguments, got %%d' %% len(result))
return result \n
def __repr__(self):
'Return a nicely formatted representation string'
return '%(typename)s(%(reprtxt)s)' %% self \n
def _asdict(self):
'Return a new OrderedDict which maps field names to their values'
return OrderedDict(zip(self._fields, self)) \n
__dict__ = property(_asdict) \n
def _replace(_self, **kwds):
'Return a new %(typename)s 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())
return result \n
def __getnewargs__(self):
'Return self as a plain tuple. Used by copy and pickle.'
return tuple(self) \n\n''' % locals()
for i, name in enumerate(field_names):
template += " %s = _property(_itemgetter(%d), doc='Alias for field number %d')\n" % (name, i, i)
# Fill-in the class template
class_definition = _class_template.format(
typename = typename,
field_names = tuple(field_names),
num_fields = len(field_names),
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))
)
if verbose:
print template
print class_definition
# Execute the template string in a temporary namespace and
# support tracing utilities by setting a value for frame.f_globals['__name__']
namespace = dict(_itemgetter=_itemgetter, __name__='namedtuple_%s' % typename,
OrderedDict=OrderedDict, _property=property, _tuple=tuple)
try:
exec template in namespace
except SyntaxError, e:
exec class_definition in namespace
except SyntaxError as e:
raise SyntaxError(e.message + ':\n' + template)
result = namespace[typename]