bar base, closes #2585

Author: nicolaskruchten

Diff for: CHANGELOG.md

@@ -8,6 +8,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 - `px.NO_COLOR` constant to override wide-form color assignment in Plotly Express ([#2614](https://github.com/plotly/plotly.py/pull/2614))
 - `facet_row_spacing` and `facet_col_spacing` added to Plotly Express cartesian 2d functions ([#2614](https://github.com/plotly/plotly.py/pull/2614))
+- `base` added to Plotly Express `bar` and `bar_polar` functions ([#2614](https://github.com/plotly/plotly.py/pull/2614))
 
 ### Fixed
 

Diff for: packages/python/plotly/plotly/express/_chart_types.py

@@ -317,6 +317,7 @@ def bar(
     hover_data=None,
     custom_data=None,
     text=None,
+    base=None,
     error_x=None,
     error_x_minus=None,
     error_y=None,
@@ -847,6 +848,7 @@ def bar_polar(
     hover_name=None,
     hover_data=None,
     custom_data=None,
+    base=None,
     animation_frame=None,
     animation_group=None,
     category_orders={},

Diff for: packages/python/plotly/plotly/express/_core.py

@@ -19,7 +19,7 @@
 
 # Declare all supported attributes, across all plot types
 direct_attrables = (
-    ["x", "y", "z", "a", "b", "c", "r", "theta", "size"]
+    ["x", "y", "z", "a", "b", "c", "r", "theta", "size", "base"]
     + ["hover_name", "text", "names", "values", "parents", "wide_cross"]
     + ["ids", "error_x", "error_x_minus", "error_y", "error_y_minus", "error_z"]
     + ["error_z_minus", "lat", "lon", "locations", "animation_group"]

Diff for: packages/python/plotly/plotly/express/_doc.py

@@ -97,6 +97,11 @@
         colref_desc,
         "Values from this column or array_like are to be interpreted according to `locationmode` and mapped to longitude/latitude.",
     ],
+    base=[
+        colref_type,
+        colref_desc,
+        "Values from this column or array_like are used to position the base of the bar.",
+    ],
     dimensions=[
         colref_list_type,
         colref_list_desc,