如何在Altair-python中取消堆积的条形图？

Question

All,

My dataset looks like following.I am trying to use Altair library to plot my visualization such that day of week is on x-axis, pickups is on y-axis, there are two plots one plot with snow= Y and other plot with snow=N, and color is based on my borough. I was successful in plotting two plots. However, all the bars are stacked on each other. I would like to unstack the plots. Below is my ALtair code.

dput of dataset

{'borough': {0: 'Bronx', 1: 'Brooklyn', 3: 'Manhattan', 4: 'Queens', 5: 'Staten Island',29094: 'Bronx', 29095: 'Brooklyn', 29097: 'Manhattan', 29098: 'Queens', 29099: 'Staten Island'}, 'pickups': {0: 152, 1: 1519, 3: 5258, 4: 405, 5: 6,29094: 67, 29095: 990, 29097: 3828, 29098: 580, 29099: 0}, 'snow': {0: 'N', 1: 'N', 3: 'N', 4: 'N', 5: 'N',29094: 'N', 29095: 'N', 29097: 'N', 29098: 'N', 29099: 'N'}, 'day_of_week': {0: 'Wednesday', 1: 'Wednesday', 3: 'Wednesday', 4: 'Wednesday', 5: 'Wednesday',29094: 'Monday', 29095: 'Monday', 29097: 'Monday', 29098: 'Monday', 29099: 'Monday'}}

Altair Code:

alt.Chart(df).mark_bar().encode(
    x='day_of_week:O',
    y='pickups:Q',
    color='borough:N',
    column='snow:N'
)

Answer 1

You can create unstacked bars using a column encoding in combination with an x encoding, following the example of Altair's Grouped Bar Chart . For your data it might look something like this:

import pandas as pd
import altair as alt

data = {'borough': {0: 'Bronx', 1: 'Brooklyn', 3: 'Manhattan', 4: 'Queens', 5: 'Staten Island',29094: 'Bronx', 29095: 'Brooklyn', 29097: 'Manhattan', 29098: 'Queens', 29099: 'Staten Island'}, 'pickups': {0: 152, 1: 1519, 3: 5258, 4: 405, 5: 6,29094: 67, 29095: 990, 29097: 3828, 29098: 580, 29099: 0}, 'snow': {0: 'N', 1: 'N', 3: 'N', 4: 'N', 5: 'N',29094: 'N', 29095: 'N', 29097: 'N', 29098: 'N', 29099: 'N'}, 'day_of_week': {0: 'Wednesday', 1: 'Wednesday', 3: 'Wednesday', 4: 'Wednesday', 5: 'Wednesday',29094: 'Monday', 29095: 'Monday', 29097: 'Monday', 29098: 'Monday', 29099: 'Monday'}}
df = pd.DataFrame(data)

alt.Chart(df).mark_bar().encode(
    x=alt.X('borough:N', axis=None),
    y='pickups:Q',
    color='borough:N',
    column='day_of_week:N'
).properties(width=80)