Display a radio button widget.

Function signature[source]

st.radio(label, options, index=0, format_func=special_internal_function, key=None, help=None, on_change=None, args=None, kwargs=None, *, disabled=False, horizontal=False, captions=None, label_visibility="visible")

Parameters

label (str)

A short label explaining to the user what this radio group is for. The label can optionally contain Markdown and supports the following elements: Bold, Italics, Strikethroughs, Inline Code, Emojis, and Links.

This also supports:

  • Emoji shortcodes, such as :+1: and :sunglasses:. For a list of all supported codes, see https://share.streamlit.io/streamlit/emoji-shortcodes.
  • LaTeX expressions, by wrapping them in "$" or "$$" (the "$$" must be on their own lines). Supported LaTeX functions are listed at https://katex.org/docs/supported.html.
  • Colored text, using the syntax :color[text to be colored], where color needs to be replaced with any of the following supported colors: blue, green, orange, red, violet, gray/grey, rainbow.

Unsupported elements are unwrapped so only their children (text contents) render. Display unsupported elements as literal characters by backslash-escaping them. E.g. 1\. Not an ordered list.

For accessibility reasons, you should never set an empty label (label="") but hide it with label_visibility if needed. In the future, we may disallow empty labels by raising an exception.

options (Iterable)

Labels for the select options in an Iterable. For example, this can be a list, numpy.ndarray, pandas.Series, pandas.DataFrame, or pandas.Index. For pandas.DataFrame, the first column is used.

Labels can include markdown as described in the label parameter and will be cast to str internally by default.

index (int or None)

The index of the preselected option on first render. If None, will initialize empty and return None until the user selects an option. Defaults to 0 (the first option).

format_func (function)

Function to modify the display of radio options. It receives the raw option as an argument and should output the label to be shown for that option. This has no impact on the return value of the radio.

key (str or int)

An optional string or integer to use as the unique key for the widget. If this is omitted, a key will be generated for the widget based on its content. Multiple widgets of the same type may not share the same key.

help (str)

An optional tooltip that gets displayed next to the radio.

on_change (callable)

An optional callback invoked when this radio's value changes.

args (tuple)

An optional tuple of args to pass to the callback.

kwargs (dict)

An optional dict of kwargs to pass to the callback.

disabled (bool)

An optional boolean, which disables the radio button if set to True. The default is False.

horizontal (bool)

An optional boolean, which orients the radio group horizontally. The default is false (vertical buttons).

captions (iterable of str or None)

A list of captions to show below each radio button. If None (default), no captions are shown.

label_visibility ("visible", "hidden", or "collapsed")

The visibility of the label. If "hidden", the label doesn't show but there is still empty space for it above the widget (equivalent to label=""). If "collapsed", both the label and the space are removed. Default is "visible".

Returns

(any)

The selected option or None if no option is selected.

Example

import streamlit as st

genre = st.radio(
    "What's your favorite movie genre",
    [":rainbow[Comedy]", "***Drama***", "Documentary :movie_camera:"],
    captions = ["Laugh out loud.", "Get the popcorn.", "Never stop learning."])

if genre == ':rainbow[Comedy]':
    st.write('You selected comedy.')
else:
    st.write("You didn\'t select comedy.")

To initialize an empty radio widget, use None as the index value:

import streamlit as st

genre = st.radio(
    "What's your favorite movie genre",
    [":rainbow[Comedy]", "***Drama***", "Documentary :movie_camera:"],
    index=None,
)

st.write("You selected:", genre)

Widgets can customize how to hide their labels with the label_visibility parameter. If "hidden", the label doesn’t show but there is still empty space for it above the widget (equivalent to label=""). If "collapsed", both the label and the space are removed. Default is "visible". Radio buttons can also be disabled with the disabled parameter, and oriented horizontally with the horizontal parameter:

import streamlit as st # Store the initial value of widgets in session state if "visibility" not in st.session_state: st.session_state.visibility = "visible" st.session_state.disabled = False st.session_state.horizontal = False col1, col2 = st.columns(2) with col1: st.checkbox("Disable radio widget", key="disabled") st.checkbox("Orient radio options horizontally", key="horizontal") with col2: st.radio( "Set label visibility πŸ‘‡", ["visible", "hidden", "collapsed"], key="visibility", label_visibility=st.session_state.visibility, disabled=st.session_state.disabled, horizontal=st.session_state.horizontal, )

Check out our video on how to use one of Streamlit's core functions, the radio button! πŸ”˜

In the video below, we'll take it a step further and learn how to combine a button, checkbox and radio button!

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