# xarray.core.groupby.DatasetGroupBy ### *class* xarray.core.groupby.DatasetGroupBy(obj, groupers, restore_coord_dims=True)[[source]](https://github.com/pydata/xarray/blob/main/xarray/core/groupby.py#L2043-L2048) #### \_\_init_\_(obj, groupers, restore_coord_dims=True)[[source]](https://github.com/pydata/xarray/blob/main/xarray/core/groupby.py#L639-L697) Create a GroupBy object * **Parameters:** * **obj** ([`Dataset`](xarray.Dataset.html.md#xarray.Dataset) or [`DataArray`](xarray.DataArray.html.md#xarray.DataArray)) – Object to group. * **grouper** ([`Grouper`](xarray.groupers.Grouper.html.md#xarray.groupers.Grouper)) – Grouper object * **restore_coord_dims** ([`bool`](https://docs.python.org/3/builtins/functions.html#bool), *default*: [`True`](https://docs.python.org/3/builtins/constants.html#True)) – If True, also restore the dimension order of multi-dimensional coordinates. ### Methods | [`__init__`](#xarray.core.groupby.DatasetGroupBy.__init__)(obj, groupers[, restore_coord_dims]) | Create a GroupBy object | |--------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------| | [`all`](xarray.core.groupby.DatasetGroupBy.all.html.md#xarray.core.groupby.DatasetGroupBy.all)([dim, keep_attrs]) | Reduce this Dataset's data by applying `all` along some dimension(s). | | [`any`](xarray.core.groupby.DatasetGroupBy.any.html.md#xarray.core.groupby.DatasetGroupBy.any)([dim, keep_attrs]) | Reduce this Dataset's data by applying `any` along some dimension(s). | | [`apply`](xarray.core.groupby.DatasetGroupBy.apply.html.md#xarray.core.groupby.DatasetGroupBy.apply)(func[, args, shortcut]) | Backward compatible implementation of `map` | | [`assign`](xarray.core.groupby.DatasetGroupBy.assign.html.md#xarray.core.groupby.DatasetGroupBy.assign)(\*\*kwargs) | Assign data variables by group. | | [`assign_coords`](xarray.core.groupby.DatasetGroupBy.assign_coords.html.md#xarray.core.groupby.DatasetGroupBy.assign_coords)([coords]) | Assign coordinates by group. | | [`count`](xarray.core.groupby.DatasetGroupBy.count.html.md#xarray.core.groupby.DatasetGroupBy.count)([dim, keep_attrs]) | Reduce this Dataset's data by applying `count` along some dimension(s). | | [`cumprod`](xarray.core.groupby.DatasetGroupBy.cumprod.html.md#xarray.core.groupby.DatasetGroupBy.cumprod)([dim, skipna, keep_attrs]) | Reduce this Dataset's data by applying `cumprod` (i.e., cumulative product) along some dimension(s). | | [`cumsum`](xarray.core.groupby.DatasetGroupBy.cumsum.html.md#xarray.core.groupby.DatasetGroupBy.cumsum)([dim, skipna, keep_attrs]) | Reduce this Dataset's data by applying `cumsum` (i.e., cumulative sum) along some dimension(s). | | [`fillna`](xarray.core.groupby.DatasetGroupBy.fillna.html.md#xarray.core.groupby.DatasetGroupBy.fillna)(value) | Fill missing values in this object by group. | | [`first`](xarray.core.groupby.DatasetGroupBy.first.html.md#xarray.core.groupby.DatasetGroupBy.first)([skipna, keep_attrs]) | Return the first element of each group along the group dimension | | [`last`](xarray.core.groupby.DatasetGroupBy.last.html.md#xarray.core.groupby.DatasetGroupBy.last)([skipna, keep_attrs]) | Return the last element of each group along the group dimension | | [`map`](xarray.core.groupby.DatasetGroupBy.map.html.md#xarray.core.groupby.DatasetGroupBy.map)(func[, args, shortcut]) | Apply a function to each Dataset in the group and concatenate them together into a new Dataset. | | [`max`](xarray.core.groupby.DatasetGroupBy.max.html.md#xarray.core.groupby.DatasetGroupBy.max)([dim, skipna, keep_attrs]) | Reduce this Dataset's data by applying `max` (i.e., maximum) along some dimension(s). | | [`mean`](xarray.core.groupby.DatasetGroupBy.mean.html.md#xarray.core.groupby.DatasetGroupBy.mean)([dim, skipna, keep_attrs]) | Reduce this Dataset's data by applying `mean` along some dimension(s). | | [`median`](xarray.core.groupby.DatasetGroupBy.median.html.md#xarray.core.groupby.DatasetGroupBy.median)([dim, skipna, keep_attrs]) | Reduce this Dataset's data by applying `median` along some dimension(s). | | [`min`](xarray.core.groupby.DatasetGroupBy.min.html.md#xarray.core.groupby.DatasetGroupBy.min)([dim, skipna, keep_attrs]) | Reduce this Dataset's data by applying `min` (i.e., minimum) along some dimension(s). | | [`prod`](xarray.core.groupby.DatasetGroupBy.prod.html.md#xarray.core.groupby.DatasetGroupBy.prod)([dim, skipna, min_count, keep_attrs]) | Reduce this Dataset's data by applying `prod` (i.e., product) along some dimension(s). | | [`quantile`](xarray.core.groupby.DatasetGroupBy.quantile.html.md#xarray.core.groupby.DatasetGroupBy.quantile)(q[, dim, method, keep_attrs, ...]) | Compute the qth quantile over each array in the groups and concatenate them together into a new array. | | [`reduce`](xarray.core.groupby.DatasetGroupBy.reduce.html.md#xarray.core.groupby.DatasetGroupBy.reduce)(func[, dim, axis, keep_attrs, shortcut]) | Reduce the items in this group by applying func along some dimension(s). | | [`shuffle_to_chunks`](xarray.core.groupby.DatasetGroupBy.shuffle_to_chunks.html.md#xarray.core.groupby.DatasetGroupBy.shuffle_to_chunks)([chunks]) | Sort or "shuffle" the underlying object. | | [`std`](xarray.core.groupby.DatasetGroupBy.std.html.md#xarray.core.groupby.DatasetGroupBy.std)([dim, skipna, ddof, keep_attrs]) | Reduce this Dataset's data by applying `std` (i.e., standard deviation) along some dimension(s). | | [`sum`](xarray.core.groupby.DatasetGroupBy.sum.html.md#xarray.core.groupby.DatasetGroupBy.sum)([dim, skipna, min_count, keep_attrs]) | Reduce this Dataset's data by applying `sum` along some dimension(s). | | [`var`](xarray.core.groupby.DatasetGroupBy.var.html.md#xarray.core.groupby.DatasetGroupBy.var)([dim, skipna, ddof, keep_attrs]) | Reduce this Dataset's data by applying `var` (i.e., variance) along some dimension(s). | | [`where`](xarray.core.groupby.DatasetGroupBy.where.html.md#xarray.core.groupby.DatasetGroupBy.where)(cond[, other]) | Return elements from self or other depending on cond. | ### Attributes | [`dims`](xarray.core.groupby.DatasetGroupBy.dims.html.md#xarray.core.groupby.DatasetGroupBy.dims) | | |---------------------------------------------------------------------------------------------------|--------------------------------------------------| | `encoded` | | | `group1d` | | | `groupers` | | | [`groups`](xarray.core.groupby.DatasetGroupBy.groups.html.md#xarray.core.groupby.DatasetGroupBy.groups) | Mapping from group labels to indices. | | `sizes` | Ordered mapping from dimension names to lengths. |