set_index

UnitsAwareDataArray.set_index(indexes: Mapping[Any, Hashable | Sequence[Hashable]] | None = None, append: bool = False, **indexes_kwargs: Hashable | Sequence[Hashable]) → Self

Set DataArray (multi-)indexes using one or more existing coordinates.

This legacy method is limited to pandas (multi-)indexes and 1-dimensional “dimension” coordinates. See set_xindex() for setting a pandas or a custom Xarray-compatible index from one or more arbitrary coordinates.

Parameters:

indexes ({dim: index, ...}) – Mapping from names matching dimensions and values given by (lists of) the names of existing coordinates or variables to set as new (multi-)index.
append (bool, default: False) – If True, append the supplied index(es) to the existing index(es). Otherwise replace the existing index(es).
**indexes_kwargs (optional) – The keyword arguments form of indexes. One of indexes or indexes_kwargs must be provided.

Returns:

obj – Another DataArray, with this data but replaced coordinates.

Return type:

DataArray

Examples

>>> arr = xr.DataArray(
...     data=np.ones((2, 3)),
...     dims=["x", "y"],
...     coords={"x": range(2), "y": range(3), "a": ("x", [3, 4])},
... )
>>> arr
<xarray.DataArray (x: 2, y: 3)> Size: 48B
array([[1., 1., 1.],
       [1., 1., 1.]])
Coordinates:
  * x        (x) int64 16B 0 1
  * y        (y) int64 24B 0 1 2
    a        (x) int64 16B 3 4
>>> arr.set_index(x="a")
<xarray.DataArray (x: 2, y: 3)> Size: 48B
array([[1., 1., 1.],
       [1., 1., 1.]])
Coordinates:
  * x        (x) int64 16B 3 4
  * y        (y) int64 24B 0 1 2