# Indexes #### SEE ALSO See the Xarray gallery on [custom indexes](https://xarray-indexes.readthedocs.io/) for more examples. ## Creating indexes | [`cftime_range`](../generated/xarray.cftime_range.html.md#xarray.cftime_range)([start, end, periods, freq, ...]) | Return a fixed frequency CFTimeIndex. | |-------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------| | [`date_range`](../generated/xarray.date_range.html.md#xarray.date_range)([start, end, periods, freq, tz, ...]) | Return a fixed frequency datetime index. | | [`date_range_like`](../generated/xarray.date_range_like.html.md#xarray.date_range_like)(source, calendar[, use_cftime]) | Generate a datetime array with the same frequency, start and end as another one, but in a different calendar. | | [`indexes.RangeIndex.arange`](../generated/xarray.indexes.RangeIndex.arange.html.md#xarray.indexes.RangeIndex.arange)([start, stop, ...]) | Create a new RangeIndex from given start, stop and step values. | | [`indexes.RangeIndex.linspace`](../generated/xarray.indexes.RangeIndex.linspace.html.md#xarray.indexes.RangeIndex.linspace)(start, stop[, ...]) | Create a new RangeIndex from given start / stop values and number of values. | ## Built-in Indexes Default, pandas-backed indexes built-in to Xarray: | [`indexes.PandasIndex`](../generated/xarray.indexes.PandasIndex.html.md#xarray.indexes.PandasIndex)(array, dim[, ...]) | Wrap a pandas.Index as an xarray compatible index. | |------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------| | [`indexes.PandasMultiIndex`](../generated/xarray.indexes.PandasMultiIndex.html.md#xarray.indexes.PandasMultiIndex)(array, dim[, ...]) | Wrap a pandas.MultiIndex as an xarray compatible index. | More complex indexes built-in to Xarray: | [`CFTimeIndex`](../generated/xarray.CFTimeIndex.html.md#xarray.CFTimeIndex)(data[, name]) | Custom Index for working with CF calendars and dates | |--------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------| | [`indexes.RangeIndex`](../generated/xarray.indexes.RangeIndex.html.md#xarray.indexes.RangeIndex)(transform) | Xarray index implementing a simple bounded 1-dimension interval with evenly spaced, monotonic floating-point values. | | [`indexes.NDPointIndex`](../generated/xarray.indexes.NDPointIndex.html.md#xarray.indexes.NDPointIndex)(tree_obj, \*, ...) | Xarray index for irregular, n-dimensional data. | | [`indexes.CoordinateTransformIndex`](../generated/xarray.indexes.CoordinateTransformIndex.html.md#xarray.indexes.CoordinateTransformIndex)(transform) | Helper class for creating Xarray indexes based on coordinate transforms. | ## Building custom indexes These classes are building blocks for more complex Indexes: | [`indexes.CoordinateTransform`](../generated/xarray.indexes.CoordinateTransform.html.md#xarray.indexes.CoordinateTransform)(coord_names, ...) | Abstract coordinate transform with dimension & coordinate names. | |--------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [`indexes.CoordinateTransformIndex`](../generated/xarray.indexes.CoordinateTransformIndex.html.md#xarray.indexes.CoordinateTransformIndex)(transform) | Helper class for creating Xarray indexes based on coordinate transforms. | | [`indexes.NDPointIndex`](../generated/xarray.indexes.NDPointIndex.html.md#xarray.indexes.NDPointIndex)(tree_obj, \*, ...) | Xarray index for irregular, n-dimensional data. | | [`indexes.TreeAdapter`](../generated/xarray.indexes.TreeAdapter.html.md#xarray.indexes.TreeAdapter)(points, \*, options) | Lightweight adapter abstract class for plugging in 3rd-party structures like [`scipy.spatial.KDTree`](https://docs.scipy.org/doc/scipy/reference/generated/scipy.spatial.KDTree.html#scipy.spatial.KDTree) or `sklearn.neighbors.KDTree` into [`NDPointIndex`](../generated/xarray.indexes.NDPointIndex.html.md#xarray.indexes.NDPointIndex). | The Index base class for building custom indexes: | [`Index`](../generated/xarray.Index.html.md#xarray.Index)() | Base class inherited by all xarray-compatible indexes. | |------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------| | [`Index.from_variables`](../generated/xarray.Index.from_variables.html.md#xarray.Index.from_variables)(variables, \*, options) | Create a new index object from one or more coordinate variables. | | [`Index.concat`](../generated/xarray.Index.concat.html.md#xarray.Index.concat)(indexes, dim[, positions]) | Create a new index by concatenating one or more indexes of the same type. | | [`Index.stack`](../generated/xarray.Index.stack.html.md#xarray.Index.stack)(variables, dim) | Create a new index by stacking coordinate variables into a single new dimension. | | [`Index.unstack`](../generated/xarray.Index.unstack.html.md#xarray.Index.unstack)() | Unstack a (multi-)index into multiple (single) indexes. | | [`Index.create_variables`](../generated/xarray.Index.create_variables.html.md#xarray.Index.create_variables)([variables]) | Maybe create new coordinate variables from this index. | | [`Index.should_add_coord_to_array`](../generated/xarray.Index.should_add_coord_to_array.html.md#xarray.Index.should_add_coord_to_array)(name, var, dims) | Define whether or not an index coordinate variable should be added to a new DataArray. | | [`Index.to_pandas_index`](../generated/xarray.Index.to_pandas_index.html.md#xarray.Index.to_pandas_index)() | Cast this xarray index to a pandas.Index object or raise a `TypeError` if this is not supported. | | [`Index.isel`](../generated/xarray.Index.isel.html.md#xarray.Index.isel)(indexers) | Maybe returns a new index from the current index itself indexed by positional indexers. | | [`Index.sel`](../generated/xarray.Index.sel.html.md#xarray.Index.sel)(labels) | Query the index with arbitrary coordinate label indexers. | | [`Index.join`](../generated/xarray.Index.join.html.md#xarray.Index.join)(other[, how]) | Return a new index from the combination of this index with another index of the same type. | | [`Index.reindex_like`](../generated/xarray.Index.reindex_like.html.md#xarray.Index.reindex_like)(other) | Query the index with another index of the same type. | | [`Index.equals`](../generated/xarray.Index.equals.html.md#xarray.Index.equals)(other, \*\*kwargs) | Compare this index with another index of the same type. | | [`Index.roll`](../generated/xarray.Index.roll.html.md#xarray.Index.roll)(shifts) | Roll this index by an offset along one or more dimensions. | | [`Index.rename`](../generated/xarray.Index.rename.html.md#xarray.Index.rename)(name_dict, dims_dict) | Maybe update the index with new coordinate and dimension names. | | [`Index.copy`](../generated/xarray.Index.copy.html.md#xarray.Index.copy)([deep]) | Return a (deep) copy of this index. | The following are useful when building custom Indexes | [`IndexSelResult`](../generated/xarray.IndexSelResult.html.md#xarray.IndexSelResult)(dim_indexers[, indexes, ...]) | Index query results. | |-----------------------------------------------------------------------------------------------------------------------|------------------------|