Change choice in st.selectbox by clicking on a button in a side bar

I am quite new to streamlit. I am seaching for a wayto change the existing choice / pick of a st.selectbox element by clicking on a button in the sidebar.

Example: st.selectbox has selected β€œA” and a chart β€œA” is rendered. I want to click on a button β€œB” in the side bar which changes the selection to β€œB” in the main window and st.selectbox, so that chart β€œB” is displayed in the main window.

Is there an easy way to realize this?

Thank you very much for your help

import pandas as pd
import streamlit as st

default_value = "A"

if st.sidebar.button("A"):
    default_value = "A"

if st.sidebar.button("B"):
    default_value = "B"

if st.sidebar.button("C"):
    default_value = "C"

df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6], "C": [7, 8, 9], "D": [10, 11, 12]})

choices = ["A", "B", "C"]
selected = st.selectbox("Select an object", choices, index=choices.index(default_value))

st.write(f"You selected {selected}")

st.line_chart(df, x="D", y=selected, use_container_width=True)

Setting the default_value in the sidebar seems to work well.

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Thank you very much, I will give it a try.

Hi @Mareus

I just realized that @blackary already had a great example code in the comments while I was creating one.

Here’s the one that I came up with:


import streamlit as st
import pandas as pd

# Callback function for A and B
def onClick(selection_input):
    if selection_input == 'A':
        st.session_state['selection'] = 0
    if selection_input == 'B':
        st.session_state['selection'] = 1

# Initialize the session state
if 'selection' not in st.session_state:
    st.session_state['selection'] = 0

# Select box
selected = st.selectbox('Make a selection:', ('A', 'B'), index=st.session_state['selection'])

# Buttons
st.button('A', on_click=onClick, args='A')
st.button('B', on_click=onClick, args='B')

# Conditional display of data visualization
if selected == 'A':
    st.subheader('Data visualization for A')
    chart_data = pd.DataFrame(
        [0.31, 0.46, 0.86, 0.91, 0.96],

if selected == 'B':
    st.subheader('Data visualization for B')
    chart_data = pd.DataFrame(
        [10, 26, 37, 56, 85],


Screen Recording 2566-04-18 at 00_scaling-0.6_fps-20_speed-10.0_duration-0-12

1 Like

Thank you very much. Both versions are exactly what I needed. Thank you so much to you two.

1 Like

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