4.4. namedtupledefs.namedtuple_original¶
4.4.1. Description¶
The original source from the Python library, here the syntax revision Python2.7. See also [namedtuple].
4.4.2. License¶
Original code copied from Standard Python Library see “namedtupledefs.namedtuple_original”:
* COPYRIGHT ORIGINAL=Copyright (c) 2001-2018 Python Software Foundation. All rights reserved. * LICENSE ORIGINAL=PSF LICENSE AGREEMENT FOR PYTHON
4.4.3. Module¶
Extract from collections.
4.4.4. Source¶
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"""
#
# Original Code: Copyright (c) 2001-2018 Python Software Foundation. All rights reserved.
# Original License: PSF LICENSE AGREEMENT FOR PYTHON
# Patches: Copyright (c) 2019 Arno-Can Uestuensoez @Ingenieurbuero Arno-Can Uestuensoez.
# All rights reserved.
# Patches License: Artistic-License-2.0 + Forced-Fairplay-Constraints
# Exception for the integration into the standard library collections:
# PSF LICENSE AGREEMENT FOR PYTHON.
#
import sys as _sys
from operator import itemgetter as _itemgetter
from keyword import iskeyword as _iskeyword
from collections import OrderedDict
################################################################################
### 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))
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)
__dict__ = _property(_asdict)
def __getstate__(self):
'Exclude the OrderedDict from pickling'
pass
{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.__doc__ # docstring for the new class
'Point(x, y)'
>>> p = Point(11, y=22) # instantiate with positional args or keywords
>>> p[0] + p[1] # indexable like a plain tuple
33
>>> x, y = p # unpack like a regular tuple
>>> x, y
(11, 22)
>>> p.x + p.y # fields also accessible by name
33
>>> d = p._asdict() # convert to a dictionary
>>> d['x']
11
>>> Point(**d) # convert from a dictionary
Point(x=11, y=22)
>>> p._replace(x=100) # _replace() is like str.replace() but targets named fields
Point(x=100, y=22)
"""
# Validate the field names. At the user's option, either generate an error
# message or automatically replace the field name with a valid name.
if isinstance(field_names, basestring):
field_names = field_names.replace(',', ' ').split()
field_names = map(str, field_names)
typename = str(typename)
if rename:
seen = set()
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):
field_names[index] = '_%d' % index
seen.add(name)
for name in [typename] + field_names:
if type(name) != str:
raise TypeError('Type names and field names must be strings')
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):
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 = 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:
raise ValueError('Encountered duplicate field name: %r' % name)
seen.add(name)
# 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 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 class_definition in namespace
except SyntaxError as e:
raise SyntaxError(e.message + ':\n' + class_definition)
result = namespace[typename]
# For pickling to work, the __module__ variable needs to be set to the frame
# where the named tuple is created. Bypass this step in environments where
# sys._getframe is not defined (Jython for example) or sys._getframe is not
# defined for arguments greater than 0 (IronPython).
try:
result.__module__ = _sys._getframe(1).f_globals.get('__name__', '__main__')
except (AttributeError, ValueError):
pass
return result
|
