Method append

pandas/core/indexes/base.py:5464–5506

Append a collection of Index options together. Parameters ---------- other : Index or list/tuple of indices Single Index or a collection of indices, which can be either a list or a tuple. Returns ------- Index

(self, other: Index | Sequence[Index])

        return False

    def append(self, other: Index | Sequence[Index]) -> Index:
        """
        Append a collection of Index options together.

        Parameters
        ----------
        other : Index or list/tuple of indices
            Single Index or a collection of indices, which can be either a list or a
            tuple.

        Returns
        -------
        Index
            Returns a new Index object resulting from appending the provided other
            indices to the original Index.

        See Also
        --------
        Index.insert : Make new Index inserting new item at location.

        Examples
        --------
        >>> idx = pd.Index([1, 2, 3])
        >>> idx.append(pd.Index([4]))
        Index([1, 2, 3, 4], dtype='int64')
        """
        to_concat = [self]

        if isinstance(other, (list, tuple)):
            to_concat += list(other)
        else:
            # error: Argument 1 to "append" of "list" has incompatible type
            # "Union[Index, Sequence[Index]]"; expected "Index"
            to_concat.append(other)  # type: ignore[arg-type]

        for obj in to_concat:
            if not isinstance(obj, Index):
                raise TypeError("all inputs must be Index")

        names = {obj.name for obj in to_concat}
        name = None if len(names) > 1 else self.name

        return self._concat(to_concat, name)

    def _concat(self, to_concat: list[Index], name: Hashable) -> Index:
        """