Streamlit clear fields of app do not work

Question

I'm trying to implement a simple front with the streamlit, this front will have a area to input a question and two bottons, 1 to submit and execute some action in the question and 1 to clear all (question and answer - the action over the question), but I cannot clear all the fields. Here is my code:

app.py

import streamlit as st

def question_and_answer_app():
    st.title("Question and Answer App")

    question = st.text_input("Enter your question:")
    answer_placeholder = st.empty()

    col1, col2 = st.columns(2)  

    if col1.button("Submit"):
        reversed_question = question[::-1]
        answer_placeholder.text("Answer: " + reversed_question) 

    if col2.button("Clear"):
        question = ""
        answer_placeholder.empty()

if __name__ == "__main__":
    question_and_answer_app()

Can someone give me a possible way to solve this?

Answer 1

You can use the argument of "key" to locate the widget and remove the input text.

import streamlit as st

def clear_text():
    st.session_state["input"] = ""

def question_and_answer_app():
    st.title("Question and Answer App")

    question = st.text_input("Enter your question:",  key="input")
    answer_placeholder = st.empty()

    col1, col2 = st.columns(2)

    if col1.button("Submit"):
        reversed_question = question[::-1]
        answer_placeholder.text("Answer: " + reversed_question)

    if col2.button("Clear", on_click=clear_text):
        answer_placeholder.empty()

if __name__ == "__main__":
    question_and_answer_app()