# xarray.Index.join

#### Index.join(other, how='inner')[[source]](https://github.com/pydata/xarray/blob/main/xarray/core/indexes.py#L317-L337)

Return a new index from the combination of this index with another
index of the same type.

Implementation is optional but required in order to support alignment.

* **Parameters:**
  * **other** ([`Index`](https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.Index.html#pandas.Index)) – The other Index object to combine with this index.
  * **join** ([`str`](https://docs.python.org/3/builtins/stdtypes.html#str), *optional*) – Method for joining the two indexes (see [`align()`](xarray.align.html.md#xarray.align)).
* **Returns:**
  **joined** ([`Index`](https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.Index.html#pandas.Index)) – A new Index object.