# xarray.core.groupby.DataArrayGroupBy.fillna

#### DataArrayGroupBy.fillna(value)[[source]](https://github.com/pydata/xarray/blob/main/xarray/core/groupby.py#L1326-L1350)

Fill missing values in this object by group.

This operation follows the normal broadcasting and alignment rules that
xarray uses for binary arithmetic, except the result is aligned to this
object (`join='left'`) instead of aligned to the intersection of
index coordinates (`join='inner'`).

* **Parameters:**
  **value** – Used to fill all matching missing values by group. Needs
  to be of a valid type for the wrapped object’s fillna
  method.
* **Returns:**
  `same type as the grouped object`

#### SEE ALSO
`Dataset.fillna`, `DataArray.fillna`