Altair returns error with single selector

Question

Trying to create a slider on the gapminder dataset from vega in Altair.

import pandas as pd
import altair as alt

from vega_datasets import data

df= data.gapminder()

yearslider = alt.selection_single(
    name="Year",
    field="year",
    init={"year": 1955},
    bind=alt.binding_range(min=1955, max=2005, step=5)
)

alt.Chart(df).mark_circle().encode(
    alt.X("fertility:Q", title=None, scale=alt.Scale(zero=False)),
    alt.Y("life_expect:Q", title="Life expectancy", 



scale=alt.Scale(zero=False)),
    alt.Size("pop:Q", scale=alt.Scale(range=[0, 1000]),
    legend=alt.Legend(orient="bottom")),
    alt.Color("cluster:N", legend=None),
    alt.Shape("cluster:N"),
    alt.Order("pop:Q", sort="descending"),
    tooltip=['country:N'],
).configure_view(fill="#fff").properties(title="Number of children by mother").interactive().add_selector(yearslider).transform_filter(yearslider)

Don't know what the error means.

altair.vegalite.v4.schema.core.SelectionDef->2->init, validating 'anyOf'

        1955 is not valid under any of the given schemas

Updated

Answer 1

I applied the following modifications to your code:

• Removed the attributes from the selection_single() - it says on the release notes selection_single and selection_multi are now deprecated; use selection_point instead.
• Removed code added after the call to interactive() function.

Modified code:

yearslider = alt.selection_single()

alt.Chart(df).mark_circle().encode(
    alt.X("fertility:Q", title=None, scale=alt.Scale(zero=False)),
    alt.Y("life_expect:Q", title="Life expectancy", 

scale=alt.Scale(zero=False)),
    alt.Size("pop:Q", scale=alt.Scale(range=[0, 1000]),
    legend=alt.Legend(orient="bottom")),
    alt.Color("cluster:N", legend=None),
    alt.Shape("cluster:N"),
    alt.Order("pop:Q", sort="descending"),
    tooltip=['country:N'],
).configure_view(fill="#fff").properties(title="Number of children by mother").interactive()

Result:

Open the Chart in the Vega Editor