Dask-expr provides a high-level expression system for Dask DataFrames, focusing on query optimization and improved organization. It became the default backend for `dask.dataframe` since Dask version 2024.3.0. The library, currently at version 2.0.0 (released January 21, 2025), is primarily maintained as part of the main Dask project, with its separate GitHub repository no longer actively maintained.
pip install dask-exprVerified import paths — ran on the pinned version, not inferred.
This quickstart demonstrates how to use Dask DataFrame, which leverages the dask-expr expression system internally for query optimization since Dask version 2024.3.0. No explicit `dask_expr` import is typically needed for standard DataFrame operations.
Ensure all dependencies are compatible with `pandas>=2`. You may need to upgrade or constrain other libraries if conflicts arise. Consider using isolated environments (conda, virtualenv) for different projects.
For contributions or detailed technical understanding, refer to the Dask main repository and documentation, specifically the `dask.dataframe` sections. Continue to install `dask-expr` if your Dask version is older than 2024.3.0 and you wish to use the query planning features. Otherwise, it is installed by default with recent Dask versions.
Use `persist()` sparingly and only when absolutely necessary, or when the full dataset is genuinely needed for subsequent complex operations. Re-evaluate if `persist()` is truly required, as the optimizer often handles intermediate computations efficiently without explicit persistence.
If 'named GroupBy Aggregations' are critical for your workflow, you might need to structure your aggregations differently (e.g., performing multiple individual aggregations and then combining them) or temporarily opt-out of the dask-expr backend if using an older Dask version where it wasn't the default (`dask.config.set({'dataframe.query-planning': False})`).Ensure `numpy` is installed in your environment. It is typically installed as a dependency when installing `dask` or `dask[array]`. You can explicitly install it via `pip install numpy` or `conda install numpy`.
Install `dask-expr` using `pip install dask-expr` or ensure a comprehensive Dask installation with `pip install "dask[dataframe]"` or `conda install dask-expr -c conda-forge`.
This is typically a compatibility issue between `dask-sql` (or another library) and the current `dask` / `dask-expr` versions. Check the documentation or GitHub issues for `dask-sql` (or the relevant library) for updated compatibility information or try installing a specific older version of `dask-sql` that is known to be compatible with your Dask/dask-expr setup.
Consult the `dask-expr` API coverage documentation (often linked in the error message itself) to confirm support for the specific function. If it's not supported, consider refactoring your code to use alternative, supported operations. As a temporary workaround, you can disable `dask-expr` query planning with `import dask; dask.config.set({'dataframe.query-planning': False})`.To enable the new backend and remove the warning, install `dask-expr` (`pip install dask-expr` or `pip install "dask[dataframe]"`) and explicitly enable query planning: `import dask; dask.config.set({'dataframe.query-planning': True})`. If you wish to suppress the warning without transitioning immediately, use `dask.config.set({'dataframe.query-planning-warning': False})`.