Altair Python horizontal bar graph with two variables in the same frame

Question

Using Altair, how can I plot in the same horizontal bar plot two variables that are in the same data frame?

I have a panda data frame that looks like this:

# initialize list of lists
data = [['AAA','71.15','FOUSA06C1Y'],
['AA','2.93','FOUSA06C1Y'],
['A','11.9','FOUSA06C1Y'],
['BBB','14.04','FOUSA06C1Y'],
['BB','0.0','FOUSA06C1Y'],
['B','0.0','FOUSA06C1Y'],
['Below B','0.0','FOUSA06C1Y'],
['Not Rated','-0.02','FOUSA06C1Y'],
['AAA','34.81744518','1404'],
['AA','47.24845367','1404'],
['A','16.66257244','1404'],
['BBB','1.271528716','1404'],
['BB / B','0.0','1404'],
['Below B','0.0','1404'],
['Short Term Rated','0.0','1404'],
['Not Rated','0.0','1404'],
['Nan','0.0','1404']]
  
# Create the pandas DataFrame
df = pd.DataFrame(data, columns=['index', 'value','fund'])

df['value'] = df['value'].astype(float)

I am able to separately horizontal bar plot these with below code:

gp_chart = alt.Chart(df).mark_bar().encode(
    alt.X('value'),
    alt.Y('index', axis=alt.Axis(grid=True)), 
    alt.Color('fund'),
    alt.Row('fund')
    )

gp_chart

Which will produce this separated graphs:

Picking part of this graph as an example (just picking A and AAA), I want to see these bars together like this:

Similar question here.

r-beginners · Answer 1 · 2023-04-28T14:02:05.193

I lack experience with altair, but I can use the filter function to create a graph with only positive values by setting the values above and below 0 and non-zero.

import altair as alt
from altair import datum

gp_chart = alt.Chart(df).mark_bar().encode(
    alt.X('value'),
    alt.Y('index', axis=alt.Axis(grid=True)), 
    alt.Color('fund'),
    alt.Row('fund')
    ).transform_filter(
    (datum.value != 0) & (datum.value >= 0)
)

gp_chart

New Version 5.0.0rc1 Although not officially released yet, it appears that grouping is possible with the latest version of the functionality. See this page

pip install altair==5.0.0rc1
import altair as alt
from altair import datum

gp_chart = alt.Chart(df).mark_bar().encode(
    alt.X('value'),
    alt.Y('index', axis=alt.Axis(grid=True)), 
    alt.Color('fund'),
    yOffset='fund'
    ).transform_filter(
    (datum.value != 0) & (datum.value >= 0)
)

gp_chart

thanks for the answer, however, I need to have the orange and blue graph in the same frame/graph. For example, in order, I need to have A for the "1404" and then the A for the "FOUSA06C1Y", then AA for the "1404" and then the AA for the "FOUSA06C1Y" if that makes sense. — FFLS, Apr 28 '23 at 12:33

Altair Python horizontal bar graph with two variables in the same frame

1 Answers1