Fix stacked barplot missing groups issue (#5428)

[AJSTYLE-lab]

Pull Request Description for #5428

Title:
Fix stacked barplot missing groups issue (#5428)

Description:
This PR addresses the bug where certain groups (commanders) with non-missing values are not displayed in stacked bar plots when using plotly.express.bar.

Problem:

When plotting a stacked bar chart of commander_perc_of_card vs. savedate_week, some commanders with values for certain weeks were missing in the overall plot.

This happens because plotly.express.bar only plots groups that exist for each specific x value (savedate_week). Missing combinations are ignored, even if other weeks have values.

Solution:

Generated all possible combinations of savedate_week and commanders using itertools.product.

Merged these combinations with the original dataset.

Filled missing commander_perc_of_card values with 0 to ensure that every commander is displayed for every week.

This guarantees that stacked barplots now show all groups, maintaining accurate visual representation.

Files Modified:

reproduce_bug.py — added a reproducible example to demonstrate the fix.

Before

After

Code:

importpandasaspdimportplotly.expressaspxfromitertoolsimportproduct# Load the dataplot_data=pd.read_csv("example_plot_data.csv") plot_data['savedate_week'] =pd.to_datetime(plot_data['savedate_week']) # Get all unique weeks and commandersall_weeks=plot_data['savedate_week'].unique() all_commanders=plot_data['commanders'].unique() # Generate full combinations of weeks and commandersfull_index=pd.DataFrame(list(product(all_weeks, all_commanders)), columns=['savedate_week','commanders']) # Merge with original data and fill missing values with 0plot_data_full=full_index.merge(plot_data, on=['savedate_week','commanders'], how='left') plot_data_full['commander_perc_of_card'] =plot_data_full['commander_perc_of_card'].fillna(0) # Create the stacked barplotfig=px.bar( plot_data_full, x="savedate_week", y="commander_perc_of_card", color="commanders" ) fig.show()

[camdecoster]

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