base.py 文件源码

def _can_reindex(self, indexer):
        """
        *this is an internal non-public method*

        Check if we are allowing reindexing with this particular indexer

        Parameters
        ----------
        indexer : an integer indexer

        Raises
        ------
        ValueError if its a duplicate axis
        """

        # trying to reindex on an axis with duplicates
        if not self.is_unique and len(indexer):
            raise ValueError("cannot reindex from a duplicate axis")