Using a selectbox and text_input, how does one reset the text_input default value back to it’s original state if a different option within selectbox is chosen?
Steps to reproduce
Run the code snippet below
Change the text_input value from 5 to 10
Change the selectbox from Project 1 to Project 2
Code snippet:
import streamlit as st
def on_text_input_change():
current_input = st.session_state.change_input
prev_input = st.session_state.prev_input
if current_input != prev_input:
del st.session_state['change_input']
def change_input(calc_default):
default = st.text_input('Change Field', calc_default, key='change_input')
return default
def choose_project():
projects = st.selectbox('Project', ['Project 1', 'Project 2', 'Project 3'], key='project', on_change=on_text_input_change)
return projects
calc_def = 5
st.session_state.prev_input = calc_def
choosen_project = choose_project()
input_text = change_input(calc_def)
for key, value in st.session_state.items():
st.write(f"{key}: {value}")
Expected behavior:
The text_input defualt value changes back to default value when a new selectbox option is selected.
Actual behavior:
You can see the session state prev_input and change_input update as you alter the two widgets. Yet, when selectbox widget is updated, the text_input value does not change back to the default value.
Hey @Binx,
I made some changes on given code snippet.
import streamlit as st
def on_text_input_change():
current_input = st.session_state.change_input
prev_input = st.session_state.prev_input
if current_input != prev_input:
st.session_state.prev_input = current_input
def change_input(calc_default):
default = st.text_input('Change Field', calc_default, key='change_input')
return default
def choose_project():
projects = st.selectbox('Project', ['Project 1', 'Project 2', 'Project 3'], key='project', on_change=on_text_input_change)
return projects
calc_def = 5
if 'prev_input' not in st.session_state:
st.session_state.prev_input = calc_def
choosen_project = choose_project()
input_text = change_input(st.session_state.prev_input)
for key, value in st.session_state.items():
st.write(f"{key}: {value}")
When the code is run initially, it checks the prev_input is not in st.session_state. If not, initializes prev_input returns to its default value.
This script will slove your problem!
I don’t think del st.session_state['change_input'] is going to make streamlit forget the state of the textbox. You need to explicitly change the state to the desired value: st.session_state["change_input"] = calc_def.
Now you can only set the state of a textbox to a string. You can just set calc_def = "5" or if you really need the number, use str(calc_def).
Streamlit will complain with a warning because you are setting the textbox state both with the value parameter and using the key, so you better remove the value: st.text_input('Change Field', key='change_input').
By doing that you no longer have an initial value for the textbox, you can add st.session_state.setdefault("change_input", calc_default) right before instantiating the textbox.
There is still room for improvement: on_text_input_change should be on_project_change and it should take the default value as a parameter, change_input is a weird name, st.session_state.prev_input is always equal to calc_def so it is not needed, etc. But it works as is.
