This page provides an overview of the major themes in pandas’ development. Each of these items requires a relatively large amount of effort to implement. These may be achieved more quickly with dedicated funding or interest from contributors.
An item being on the roadmap does not mean that it will necessarily happen, even with unlimited funding. During the implementation period we may discover issues preventing the adoption of the feature.
Additionally, an item not being on the roadmap does not exclude it from inclusion in pandas. The roadmap is intended for larger, fundamental changes to the project that are likely to take months or years of developer time. Smaller-scoped items will continue to be tracked on our issue tracker.
See Roadmap Evolution for proposing changes to this document.
Pandas Extension types allow for extending NumPy types with custom data types and array storage. Pandas uses extension types internally, and provides an interface for 3rd-party libraries to define their own custom data types.
Many parts of pandas still unintentionally convert data to a NumPy array. These problems are especially pronounced for nested data.
We’d like to improve the handling of extension arrays throughout the library, making their behavior more consistent with the handling of NumPy arrays. We’ll do this by cleaning up pandas’ internals and adding new methods to the extension array interface.
Currently, pandas stores text data in an object -dtype NumPy array. The current implementation has two primary drawbacks: First, object -dtype is not specific to strings: any Python object can be stored in an object -dtype array, not just strings. Second: this is not efficient. The NumPy memory model isn’t especially well-suited to variable width text data.
object
To solve the first issue, we propose a new extension type for string data. This will initially be opt-in, with users explicitly requesting dtype="string". The array backing this string dtype may initially be the current implementation: an object -dtype NumPy array of Python strings.
dtype="string"
To solve the second issue (performance), we’ll explore alternative in-memory array libraries (for example, Apache Arrow). As part of the work, we may need to implement certain operations expected by pandas users (for example the algorithm used in, Series.str.upper). That work may be done outside of pandas.
Series.str.upper
Apache Arrow is a cross-language development platform for in-memory data. The Arrow logical types are closely aligned with typical pandas use cases.
We’d like to provide better-integrated support for Arrow memory and data types within pandas. This will let us take advantage of its I/O capabilities and provide for better interoperability with other languages and libraries using Arrow.
We’d like to replace pandas current internal data structures (a collection of 1 or 2-D arrays) with a simpler collection of 1-D arrays.
Pandas internal data model is quite complex. A DataFrame is made up of one or more 2-dimensional “blocks”, with one or more blocks per dtype. This collection of 2-D arrays is managed by the BlockManager.
The primary benefit of the BlockManager is improved performance on certain operations (construction from a 2D array, binary operations, reductions across the columns), especially for wide DataFrames. However, the BlockManager substantially increases the complexity and maintenance burden of pandas.
By replacing the BlockManager we hope to achieve
Substantially simpler code
Easier extensibility with new logical types
Better user control over memory use and layout
Improved micro-performance
Option to provide a C / Cython API to pandas’ internals
See these design documents for more.
The code for getting and setting values in pandas’ data structures needs refactoring. In particular, we must clearly separate code that converts keys (e.g., the argument to DataFrame.loc) to positions from code that uses these positions to get or set values. This is related to the proposed BlockManager rewrite. Currently, the BlockManager sometimes uses label-based, rather than position-based, indexing. We propose that it should only work with positional indexing, and the translation of keys to positions should be entirely done at a higher level.
DataFrame.loc
Indexing is a complicated API with many subtleties. This refactor will require care and attention. More details are discussed at https://github.com/pandas-dev/pandas/wiki/(Tentative)-rules-for-restructuring-indexing-code
Numba is a JIT compiler for Python code. We’d like to provide ways for users to apply their own Numba-jitted functions where pandas accepts user-defined functions (for example, Series.apply(), DataFrame.apply(), DataFrame.applymap(), and in groupby and window contexts). This will improve the performance of user-defined-functions in these operations by staying within compiled code.
Series.apply()
DataFrame.apply()
DataFrame.applymap()
We’d like to improve the content, structure, and presentation of the pandas documentation. Some specific goals include
Overhaul the HTML theme with a modern, responsive design (GH15556)
Improve the “Getting Started” documentation, designing and writing learning paths for users different backgrounds (e.g. brand new to programming, familiar with other languages like R, already familiar with Python).
Improve the overall organization of the documentation and specific subsections of the documentation to make navigation and finding content easier.
Pandas uses airspeed velocity to monitor for performance regressions. ASV itself is a fabulous tool, but requires some additional work to be integrated into an open source project’s workflow.
The asv-runner organization, currently made up of pandas maintainers, provides tools built on top of ASV. We have a physical machine for running a number of project’s benchmarks, and tools managing the benchmark runs and reporting on results.
We’d like to fund improvements and maintenance of these tools to
Be more stable. Currently, they’re maintained on the nights and weekends when a maintainer has free time.
Tune the system for benchmarks to improve stability, following https://pyperf.readthedocs.io/en/latest/system.html
Build a GitHub bot to request ASV runs before a PR is merged. Currently, the benchmarks are only run nightly.
Pandas continues to evolve. The direction is primarily determined by community interest. Everyone is welcome to review existing items on the roadmap and to propose a new item.
Each item on the roadmap should be a short summary of a larger design proposal. The proposal should include
Short summary of the changes, which would be appropriate for inclusion in the roadmap if accepted.
Motivation for the changes.
An explanation of why the change is in scope for pandas.
Detailed design: Preferably with example-usage (even if not implemented yet) and API documentation
API Change: Any API changes that may result from the proposal.
That proposal may then be submitted as a GitHub issue, where the pandas maintainers can review and comment on the design. The pandas mailing list should be notified of the proposal.
When there’s agreement that an implementation would be welcome, the roadmap should be updated to include the summary and a link to the discussion issue.