3 7 Radio Buttons Explained

Key Concepts

• st.radio: A widget that allows users to select one option from a list.
• Options: The list of choices available to the user.
• Default Selection: The option that is pre-selected when the widget is first displayed.
• Interactive Use: How to use radio buttons to create interactive applications.

st.radio

st.radio is a Streamlit widget that provides a set of radio buttons. Users can select one option from the list provided. This widget is particularly useful when you want to restrict the user to a single choice from a set of options.

Options

The st.radio function accepts a list of options as its main parameter. Each item in the list represents a radio button that the user can select. The order of the options in the list determines the order in which the radio buttons are displayed.

Default Selection

You can specify a default selection for the radio buttons by passing the index of the desired option to the index parameter. This ensures that a particular option is pre-selected when the widget is first displayed.

Interactive Use

Using st.radio, you can create interactive applications where users can make choices that affect the output. For example, you can create a quiz where users select answers from a list of options.

Examples

Here are some examples to illustrate the use of st.radio:

import streamlit as st

st.title("Radio Buttons Example")

# Basic radio buttons
option = st.radio("Choose an option", ["Option 1", "Option 2", "Option 3"])
st.write(f"You selected: {option}")

# Radio buttons with default selection
default_option = 1
selected_option = st.radio("Choose an option", ["Option A", "Option B", "Option C"], index=default_option)
st.write(f"You selected: {selected_option}")

# Interactive quiz
question = "What is the capital of France?"
answers = ["Paris", "London", "Berlin", "Madrid"]
correct_answer = "Paris"

user_answer = st.radio(question, answers)
if user_answer == correct_answer:
    st.write("Correct!")
else:
    st.write("Incorrect. The correct answer is Paris.")
    

In the first example, basic radio buttons are created with three options. The second example demonstrates setting a default selection. The third example shows how to create an interactive quiz using radio buttons.