def reindex(self, target, method=None, level=None, limit=None,
                tolerance=None):
        """
        Create index with target's values (move/add/delete values as necessary)

        Parameters
        ----------
        target : an iterable

        Returns
        -------
        new_index : pd.Index
            Resulting index
        indexer : np.ndarray or None
            Indices of output values in original index

        """
        # GH6552: preserve names when reindexing to non-named target
        # (i.e. neither Index nor Series).
        preserve_names = not hasattr(target, 'name')

        # GH7774: preserve dtype/tz if target is empty and not an Index.
        target = _ensure_has_len(target)  # target may be an iterator

        if not isinstance(target, Index) and len(target) == 0:
            attrs = self._get_attributes_dict()
            attrs.pop('freq', None)  # don't preserve freq
            target = self._simple_new(None, dtype=self.dtype, **attrs)
        else:
            target = _ensure_index(target)

        if level is not None:
            if method is not None:
                raise TypeError('Fill method not supported if level passed')
            _, indexer, _ = self._join_level(target, level, how='right',
                                             return_indexers=True)
        else:
            if self.equals(target):
                indexer = None
            else:

                if self.is_unique:
                    indexer = self.get_indexer(target, method=method,
                                               limit=limit,
                                               tolerance=tolerance)
                else:
                    if method is not None or limit is not None:
                        raise ValueError("cannot reindex a non-unique index "
                                         "with a method or limit")
                    indexer, missing = self.get_indexer_non_unique(target)

        if preserve_names and target.nlevels == 1 and target.name != self.name:
            target = target.copy()
            target.name = self.name

        return target, indexer
dataset/ETHPy150Open pydata/pandas/pandas/indexes/base.py/Index.reindex/original