# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2024)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from dataclasses import dataclass
from textwrap import dedent
from typing import TYPE_CHECKING, Any, Callable, Generic, Sequence, cast
from streamlit.elements.form import current_form_id
from streamlit.elements.utils import (
check_cache_replay_rules,
check_callback_rules,
check_session_state_rules,
get_label_visibility_proto_value,
maybe_coerce_enum,
)
from streamlit.errors import StreamlitAPIException
from streamlit.proto.Radio_pb2 import Radio as RadioProto
from streamlit.runtime.metrics_util import gather_metrics
from streamlit.runtime.scriptrunner import ScriptRunContext, get_script_run_ctx
from streamlit.runtime.state import (
WidgetArgs,
WidgetCallback,
WidgetKwargs,
get_session_state,
register_widget,
)
from streamlit.runtime.state.common import compute_widget_id, save_for_app_testing
from streamlit.type_util import (
Key,
LabelVisibility,
OptionSequence,
T,
check_python_comparable,
ensure_indexable,
maybe_raise_label_warnings,
to_key,
)
from streamlit.util import index_
if TYPE_CHECKING:
from streamlit.delta_generator import DeltaGenerator
@dataclass
class RadioSerde(Generic[T]):
options: Sequence[T]
index: int | None
def serialize(self, v: object) -> int | None:
if v is None:
return None
return 0 if len(self.options) == 0 else index_(self.options, v)
def deserialize(
self,
ui_value: int | None,
widget_id: str = "",
) -> T | None:
idx = ui_value if ui_value is not None else self.index
return (
self.options[idx]
if idx is not None
and len(self.options) > 0
and self.options[idx] is not None
else None
)
class RadioMixin:
@gather_metrics("radio")
def radio(
self,
label: str,
options: OptionSequence[T],
index: int | None = 0,
format_func: Callable[[Any], Any] = str,
key: Key | None = None,
help: str | None = None,
on_change: WidgetCallback | None = None,
args: WidgetArgs | None = None,
kwargs: WidgetKwargs | None = None,
*, # keyword-only args:
disabled: bool = False,
horizontal: bool = False,
captions: Sequence[str] | None = None,
label_visibility: LabelVisibility = "visible",
) -> T | None:
r"""Display a radio button widget.
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 and background colors for text, using the syntax
``:color[text to be colored]`` and ``:color-background[text to be colored]``,
respectively. ``color`` must be replaced with any of the following
supported colors: blue, green, orange, red, violet, gray/grey, rainbow.
For example, you can use ``:orange[your text here]`` or
``:blue-background[your text here]``.
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.")
.. output::
https://doc-radio.streamlit.app/
height: 300px
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)
.. output::
https://doc-radio-empty.streamlit.app/
height: 300px
"""
ctx = get_script_run_ctx()
return self._radio(
label=label,
options=options,
index=index,
format_func=format_func,
key=key,
help=help,
on_change=on_change,
args=args,
kwargs=kwargs,
disabled=disabled,
horizontal=horizontal,
captions=captions,
label_visibility=label_visibility,
ctx=ctx,
)
def _radio(
self,
label: str,
options: OptionSequence[T],
index: int | None = 0,
format_func: Callable[[Any], Any] = str,
key: Key | None = None,
help: str | None = None,
on_change: WidgetCallback | None = None,
args: WidgetArgs | None = None,
kwargs: WidgetKwargs | None = None,
*, # keyword-only args:
disabled: bool = False,
horizontal: bool = False,
label_visibility: LabelVisibility = "visible",
captions: Sequence[str] | None = None,
ctx: ScriptRunContext | None,
) -> T | None:
key = to_key(key)
check_cache_replay_rules()
check_callback_rules(self.dg, on_change)
check_session_state_rules(default_value=None if index == 0 else index, key=key)
maybe_raise_label_warnings(label, label_visibility)
opt = ensure_indexable(options)
check_python_comparable(opt)
id = compute_widget_id(
"radio",
user_key=key,
label=label,
options=[str(format_func(option)) for option in opt],
index=index,
key=key,
help=help,
horizontal=horizontal,
captions=captions,
form_id=current_form_id(self.dg),
page=ctx.page_script_hash if ctx else None,
)
if not isinstance(index, int) and index is not None:
raise StreamlitAPIException(
"Radio Value has invalid type: %s" % type(index).__name__
)
if index is not None and len(opt) > 0 and not 0 <= index < len(opt):
raise StreamlitAPIException(
"Radio index must be between 0 and length of options"
)
def handle_captions(caption: str | None) -> str:
if caption is None:
return ""
elif isinstance(caption, str):
return caption
else:
raise StreamlitAPIException(
f"Radio captions must be strings. Passed type: {type(caption).__name__}"
)
session_state = get_session_state().filtered_state
if key is not None and key in session_state and session_state[key] is None:
index = None
radio_proto = RadioProto()
radio_proto.id = id
radio_proto.label = label
if index is not None:
radio_proto.default = index
radio_proto.options[:] = [str(format_func(option)) for option in opt]
radio_proto.form_id = current_form_id(self.dg)
radio_proto.horizontal = horizontal
radio_proto.disabled = disabled
radio_proto.label_visibility.value = get_label_visibility_proto_value(
label_visibility
)
if captions is not None:
radio_proto.captions[:] = map(handle_captions, captions)
if help is not None:
radio_proto.help = dedent(help)
serde = RadioSerde(opt, index)
widget_state = register_widget(
"radio",
radio_proto,
user_key=key,
on_change_handler=on_change,
args=args,
kwargs=kwargs,
deserializer=serde.deserialize,
serializer=serde.serialize,
ctx=ctx,
)
widget_state = maybe_coerce_enum(widget_state, options, opt)
if widget_state.value_changed:
if widget_state.value is not None:
serialized_value = serde.serialize(widget_state.value)
if serialized_value is not None:
radio_proto.value = serialized_value
radio_proto.set_value = True
if ctx:
save_for_app_testing(ctx, id, format_func)
self.dg._enqueue("radio", radio_proto)
return widget_state.value
@property
def dg(self) -> DeltaGenerator:
"""Get our DeltaGenerator."""
return cast("DeltaGenerator", self)