mirror of
https://github.com/python/cpython.git
synced 2025-10-31 13:41:24 +00:00
72 lines
2.7 KiB
Python
72 lines
2.7 KiB
Python
__all__ = ['deque', 'defaultdict', 'NamedTuple']
|
|
|
|
from _collections import deque, defaultdict
|
|
from operator import itemgetter as _itemgetter
|
|
import sys as _sys
|
|
|
|
def NamedTuple(typename, s, verbose=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] # works just like the tuple (11, 22)
|
|
33
|
|
>>> x, y = p # unpacks just like a tuple
|
|
>>> x, y
|
|
(11, 22)
|
|
>>> p.x + p.y # fields also accessable by name
|
|
33
|
|
>>> p # readable __repr__ with name=value style
|
|
Point(x=11, y=22)
|
|
>>> p.__replace__('x', 100) # __replace__() is like str.replace() but targets a named field
|
|
Point(x=100, y=22)
|
|
>>> d = dict(zip(p.__fields__, p)) # use __fields__ to make a dictionary
|
|
>>> d['x']
|
|
11
|
|
|
|
"""
|
|
|
|
field_names = tuple(s.replace(',', ' ').split()) # names separated by spaces and/or commas
|
|
if not ''.join((typename,) + field_names).replace('_', '').isalnum():
|
|
raise ValueError('Type names and field names can only contain alphanumeric characters and underscores')
|
|
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)'
|
|
__slots__ = ()
|
|
__fields__ = %(field_names)r
|
|
def __new__(cls, %(argtxt)s):
|
|
return tuple.__new__(cls, (%(argtxt)s))
|
|
def __repr__(self):
|
|
return '%(typename)s(%(reprtxt)s)' %% self
|
|
def __replace__(self, field, value):
|
|
'Return a new %(typename)s object replacing one field with a new value'
|
|
return %(typename)s(**dict(zip(%(field_names)r, self) + [(field, value)])) \n''' % locals()
|
|
for i, name in enumerate(field_names):
|
|
template += ' %s = property(itemgetter(%d))\n' % (name, i)
|
|
if verbose:
|
|
print template
|
|
m = dict(itemgetter=_itemgetter)
|
|
exec template in m
|
|
result = m[typename]
|
|
if hasattr(_sys, '_getframe'):
|
|
result.__module__ = _sys._getframe(1).f_globals['__name__']
|
|
return result
|
|
|
|
|
|
|
|
|
|
|
|
|
|
if __name__ == '__main__':
|
|
# verify that instances can be pickled
|
|
from cPickle import loads, dumps
|
|
Point = NamedTuple('Point', 'x, y', True)
|
|
p = Point(x=10, y=20)
|
|
assert p == loads(dumps(p))
|
|
|
|
import doctest
|
|
TestResults = NamedTuple('TestResults', 'failed attempted')
|
|
print TestResults(*doctest.testmod())
|