Nested Selectbox Component

[mkleinbort-ic]

Checklist

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Summary

A streamlit component (or configuration of selectbox) to allow for nesting options.

Why?

This is an issue when there are logically grouped options in a selectbox.

Currently either the selectbox list of options gets very long, or the user has to use more than one action to choose the selection.

How?

The simplest API change I can imagine is to pass a dict of options and sub-options to st.selectbox

Illustratively, to create this:

You could write:

st.selectbox('Nested Selectbox', options={
    'Option 1': ['Option 1.1', 'Option 1.2', 'Option 1.3'],
    'Option 2': ['Option 2.1', 'Option 2.2', 'Option 2.3'],
    'Option 3': ['Option 3.1', 'Option 3.2', 'Option 3.3'],
})

Additional Context

I saw the st_ant_tree custom component, but the styling is far from what I'm looking for.

Admittedly, this could be a good use case for a custom component.

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[mkleinbort-ic]

streamlit-antd-components's Cascader might be a fix.