Version 4.2.1

Note: This version requires jsonschema>=4.5.0 see (#2857).

Bug Fixes

• Disable uri-reference format check in jsonsschema (#2771).
• Replace iteritems with items due to pandas deprecation (#2683).

Maintenance

• Add deprecation and removal warnings for Vega-Lite v3 wrappers and Vega v5 wrappers (#2843).

Version 4.2.0

• Update Vega-Lite from version 4.8.1 to version 4.17.0; see Vega-Lite Release Notes.

Enhancements

• Pie charts are now supported through the use of mark_arc. (Examples: eg. Pie Chart and Radial Chart)
• Support for the datum encoding specifications from Vega-Lite; see Vega-Lite Datum Definition. (Examples: Line Chart with datum and Line Chart with datum for color.)
• angle encoding can now be used to control point styles (Example: Wind Vector Map)
• Support for serialising pandas nullable data types for float data (#2399).
• Automatically create an empty data object when Chart is called without a data parameter (#2515).
• Allow the use of pathlib Paths when saving charts (#2355).
• Support deepcopy for charts (#2403).

Bug Fixes

• Fix to_dict() for nested selections (#2120).
• Fix item access for expressions (#2099).

Version 4.1.0

• Minimum Python version is now 3.6
• Update Vega-Lite to version 4.8.1; many new features and bug fixes from Vega-Lite versions 4.1 through 4.8; see Vega-Lite Release Notes.

Enhancements

• strokeDash encoding can now be used to control line styles (Example: Multi Series Line Chart
• chart.save() now relies on altair_saver for more flexibility (#1943).
• New chart.show() method replaces chart.serve(), and relies on altair_viewer to allow offline viewing of charts (#1988).

Bug Fixes

• Support Python 3.8 (#1958)
• Support multiple views in JupyterLab (#1986)
• Support numpy types within specifications (#1914)
• Support pandas nullable ints and string types (#1924)

Maintenance

• Altair now uses black and flake8 for maintaining code quality & consistency.

Version 4.0.1

Bug fixes

• Update Vega-Lite version to 4.0.2
• Fix issue with duplicate chart divs in HTML renderer (#1888)

Version 4.0.0 Release

Altair Version 4.0.0 release

Version 4.0.0 is based on Vega-Lite version 4.0, which you can read about at
https://github.com/vega/vega-lite/releases/tag/v4.0.0.

It is the first version of Altair to drop Python 2 compatibility, and is tested
on Python 3.5 and newer.

Enhancements

• Support for interactive legends: (Example)
  

• Responsive chart width and height: (Example)
  

• Bins responsive to selections: (Example)
  

• New pivot transform: (Example)
  

• New Regression transform: (Example)
  

• New LOESS transform: (Example)
  

• New density transform: (Example)
  

• Image mark (Example)
  

• New default html renderer, directly compatible with Jupyter Notebook and
  JupyterLab without the need for frontend extensions, as well as tools like
  nbviewer and nbconvert, and related notebook environments such as Zeppelin,
  Colab, Kaggle Kernels, and DataBricks. To enable the old default renderer, use:

  alt.renderers.enable('mimetype')
  

• Support per-corner radius for bar marks: (Example)
  

Grammar Changes

• Sort-by-field can now use the encoding name directly. So instead of

  alt.Y('y:Q', sort=alt.EncodingSortField('x_field', order='descending'))
  

  you can now use::

  alt.Y('y:Q', sort="-x")
  

• The rangeStep argument to :class:Scale and :meth:Chart.configure_scale is deprecated.
  instead, use chart.properties(width={"step": rangeStep}) or
  chart.configure_view(step=rangeStep).

• align, center, spacing, and columns are no longer valid chart properties, but
  are moved to the encoding classes to which they refer.

Version 3.3.0

Version 3.3.0

released Nov 27, 2019

Last release to support Python 2

Enhancements

• Add inheritance structure to low-level schema classes (#1803)
• Add html renderer which works across frontends (#1793)
• Support Python 3.8 (#1740, #1781)
• Add :G shorthand for geojson type (#1714)
• Add data generator interface: alt.sequence, alt.graticule,
  alt.sphere() (#1667, #1687)
• Support geographic data sources via __geo_interface__ (#1664)

Bug Fixes

• Support pickle and copy.deepcopy for chart objects (#1805)
• Fix bug when specifying count() within transform_joinaggregate() (#1751)
• Fix LayerChart.add_selection (#1794)
• Fix arguments to project() method (#1717)
• Fix composition of multiple selections (#1707)

Version 3.2.0

Version 3.2.0 (released August 5, 2019)

Upgraded to Vega-Lite version 3.4 (See Vega-Lite 3.4 Release Notes).

Following are changes to Altair in addition to those that came with VL 3.4:

Enhancements

• Selector values can be used directly in expressions (#1599)
• Top-level chart repr is now truncated to improve readability of error
  messages (#1572)

Bug Fixes

• top-level add_selection methods now delegate to sub-charts. Previously
  they produced invalid charts (#1607)
• Unsupported mark_*() methods removed from LayerChart (#1607)
• New encoding channels are properly parsed (#1597)
• Data context is propagated when encodings are specified as lists (#1587)

Backward-Incompatible Changes

• alt.LayerChart no longer has mark_*() methods, because they never
  produced valid chart specifications) (#1607)

Version 3.1.0

Update includes full compatibility with version 3.3 of Vega-Lite.

Enhancements

• Added support for vega themes via alt.themes.enable(theme_name) (#1539)

• Added an alt.renderers.disable_max_rows() method for disabling the maximum rows check (#1538)

• Improved user-facing warnings/errors around layering and faceting (#1535).

• data argument is now properly handled by Chart.properties (#1525)

• Compound charts (layer, concat, hconcat, vconcat) now move data to the top level by default. In particular, this means that the facet() method can now be called directly on a layered chart without having to change how data is specified. (#1521)

• alt.LayerChart now supports mark_*() methods. If a layer specifies a mark at the top level, all child charts will inherit it (unless they override it explicitly).

• alt.Chart.facet() now handles wrapped facets; for example: chart.facet('column_name', columns=5) See altair/examples/us_population_over_time_facet.py for a more complete example.

Bug fixes

• Make chart.serve() and chart.save() respect the data transformer setting (#1538)

• Fixed a deserialization bug for certain chart specs in schemapi (#1543)

Backward-Incompatible Changes

• alt.Chart.facet() now accepts a wrapped facet encoding as a first positional argument, rather than a row encoding. The following are examples of old invocations, and the equivalent new invocations:

• chart.facet(row='col1', column='col2'): unchanged

• chart.facet('col1', 'col2'): change to chart.facet(row='col1', column='col2')

• chart.facet('col1'): change to chart.facet(row='col1')

In each case, the new invocations are compatible back to Altair 2.X.

• Several of the encoding channels added in 3.0 have had their capitalization corrected to better match the names used in the schema:

• alt.Fillopacity -> alt.FillOpacity

• alt.Strokeopacity -> alt.StrokeOpacity

• alt.Strokewidth -> alt.StrokeWidth

• alt.Xerror -> alt.XError

• alt.Xerror2 -> alt.XError2

• alt.Yerror -> alt.YError

• alt.Yerror2 -> alt.YError2

Version 3.0.1

Fix version info bug for HTML output and Colab & Kaggle renderers.

Version 3.0

Update to Vega-Lite 3.2 and Vega 5.3 & support all new features. See
https://github.com/vega/vega-lite/releases/tag/v3.0.0 for Vega-Lite
feature lists.

Highlights

• new compound marks: mark_boxplot(), mark_errorband(), mark_errorbar()
• new transforms: transform_impute(), transform_joinaggregate(), transform_flatten() transform_fold(), transform_sample(), transform_stack()
• new facet encoding that is similar to the row and column encoding, but allows for wrapped facets
• new alt.concat() function that is similar to alt.hconcat and alt.vconcat, but allows for more general wrapped concatenation
• new columns keyword that allows wrapped faceting, repeating, and concatenation.
• many, many bug fixes
• tooltips can now be automatically populated using the tooltip mark configuration.
• ability to specify initial conditions for selections