Streamlit Multiselectbox with lists as options

I want to create a multiselectbox where a user can choose between multiple lists instead of strings.

A quick example what i’m trying to achieve:

list_1 = ['1','2','3','4']
list_2 =  ['a','b','c','d']
list_3 =  ['!','?','€','%']

choice = st.multiselect('Choose List',[list_1,list_2,list_3])
 
df = df[df['symbol'].isin(choice )]

While the example above sort of works it will logically display the list inside the selectbox.
But i would like to select a string so “choice” is equal to the selected list.
I would also need to join the lists if multiple options are selected.

So for example if i select "list_1"

choice = ['1','2','3','4']

And if i would select "list_1" and "list_3"

choice = ['1','2','3','4','!','?','€','%']

I need a little hint here what would be the best way to do this.

If I understand your idea correctly, you can use a dictionary that the keys are the names of your lists and values are equal to each list.

import streamlit as st


list_1 = ['1','2','3','4']
list_2 =  ['a','b','c','d']
list_3 =  ['!','?','€','%']

lists = {
    'List 1': list_1,
    'List 2': list_2,
    'List 3': list_3
}


choice = st.multiselect('Choose List',lists.keys())
 
st.write('You selected:', [lists[x] for x in choice if x in lists.keys()])

selected = []
for i in choice:
    selected.extend(lists[i])

st.write("Combine lists that you selected", selected)