_odict.py 文件源码

def __setitem__(self, index, name):
        """
        You cannot assign to keys, but you can do slice assignment to re-order
        them.

        You can only do slice assignment if the new set of keys is a reordering
        of the original set.
        """
        if isinstance(index, types.SliceType):
            # FIXME: efficiency?
            # check length is the same
            indexes = range(len(self._main._sequence))[index]
            if len(indexes) != len(name):
                raise ValueError('attempt to assign sequence of size %s '
                    'to slice of size %s' % (len(name), len(indexes)))
            # check they are the same keys
            # FIXME: Use set
            old_keys = self._main._sequence[index]
            new_keys = list(name)
            old_keys.sort()
            new_keys.sort()
            if old_keys != new_keys:
                raise KeyError('Keylist is not the same as current keylist.')
            orig_vals = [self._main[k] for k in name]
            del self._main[index]
            vals = zip(indexes, name, orig_vals)
            vals.sort()
            for i, k, v in vals:
                if self._main.strict and k in self._main:
                    raise ValueError('slice assignment must be from '
                        'unique keys')
                self._main.insert(i, k, v)
        else:
            raise ValueError('Cannot assign to keys')

    ### following methods pinched from UserList and adapted ###