[FIXED] Why are both of my graphs not showing when using Altair on Spyder?

Issue

Code for two graphs. Ran this code a couple of times, and for some reason all that's showing up is the histogram. It's also important to mention that I am using Spyder IDE as well, if that makes any difference. Oh....and I've also tried graph|hist... but nothing

    import altair as alt
    import pandas as pd
   
    #import csv
    acs = pd.read_csv('C:/Users/Andrew/anaconda3/mydata/acs2020.csv')
    acs.head()
    
    
    interval = alt.selection_interval()

    #build point graph
    graph = alt.Chart(acs).mark_point(opacity=1).encode(
        x = ('Trade #'),
        y = ('Balance'),
        color = alt.Color('Item',scale=alt.Scale(scheme='tableau10')),
        tooltip = [alt.Tooltip('Type'),
                   alt.Tooltip('Profit'),
                   alt.Tooltip('Ticket:N')
                  ]
    ).properties(
        width = 900
    )

    #build histogram
    hist = alt.Chart(acs).mark_bar().encode(
        x = 'count()',
        y = 'Item',
        color = 'Item'
    ).properties(
        width = 800,
        height = 80
    ).add_selection(
        interval
    )
    #show graphs
    graph&hist.show()

Solution

You need to add parentheses to the last line: (graph & hist).show().

---

Explanation: when you write something like

graph&hist.show()

Python dictates the order of operations, and method calls have higher precedence than binary operators. This means that it is equivalent to:

(graph) & (hist.show())

You are showing the hist chart, and then concatenating the return value of the show() method, which is None, to the graph chart, which will result in a ValueError when the histogram chart is closed.

Instead, if you want to show the result of the graph & hist operation, you need to use parentheses to indicate this:

(graph & hist).show()

Answered By - jakevdp