41 lines
1.7 KiB
Python
41 lines
1.7 KiB
Python
# http://code.activestate.com/recipes/500261/
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from operator import itemgetter
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import sys
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def __from_iterable__(cls,arg):
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return cls.__new__(cls,*arg)
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def NamedTuple(typename, field_names):
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if isinstance(field_names, str):
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field_names = field_names.split()
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nargs = len(field_names)
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def __new__(cls, *args, **kwds):
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if (len(args) == 1) and (getattr(args[0], '__iter__', False)):
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args = tuple(name for name in args[0])
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if kwds:
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try:
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args += tuple(kwds[name] for name in field_names[len(args):])
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except KeyError, name:
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raise TypeError('%s missing required argument: %s' % (typename, name))
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if len(args) != nargs:
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raise TypeError('%s takes exactly %d arguments (%d given)' % (typename, nargs, len(args)))
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return tuple.__new__(cls, args)
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repr_template = '%s(%s)' % (typename, ', '.join('%s=%%r' % name for name in field_names))
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m = dict(vars(tuple)) # pre-lookup superclass methods (for faster lookup)
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m.update(__doc__= '%s(%s)' % (typename, ', '.join(field_names)),
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__slots__ = (), # no per-instance dict (so instances are same size as tuples)
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__new__ = __new__,
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__repr__ = lambda self, _format=repr_template.__mod__: _format(self),
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__module__ = sys._getframe(1).f_globals['__name__'],
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__field_names__ = tuple(field_names),
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__from_iterable__=classmethod(__from_iterable__),
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)
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m.update((name, property(itemgetter(index))) for index, name in enumerate(field_names))
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return type(typename, (tuple,), m)
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