team-10/env/Lib/site-packages/streamlit/elements/widgets/multiselect.py
2025-08-02 07:34:44 +02:00

554 lines
20 KiB
Python

# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2025)
#
# 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 collections.abc import Sequence
from textwrap import dedent
from typing import TYPE_CHECKING, Any, Callable, Generic, Literal, cast, overload
from streamlit.dataframe_util import OptionSequence, convert_anything_to_list
from streamlit.elements.lib.form_utils import current_form_id
from streamlit.elements.lib.layout_utils import (
LayoutConfig,
WidthWithoutContent,
validate_width,
)
from streamlit.elements.lib.options_selector_utils import (
convert_to_sequence_and_check_comparable,
create_mappings,
get_default_indices,
maybe_coerce_enum_sequence,
)
from streamlit.elements.lib.policies import (
check_widget_policies,
maybe_raise_label_warnings,
)
from streamlit.elements.lib.utils import (
Key,
LabelVisibility,
compute_and_register_element_id,
get_label_visibility_proto_value,
save_for_app_testing,
to_key,
)
from streamlit.errors import (
StreamlitSelectionCountExceedsMaxError,
)
from streamlit.proto.MultiSelect_pb2 import MultiSelect as MultiSelectProto
from streamlit.runtime.metrics_util import gather_metrics
from streamlit.runtime.scriptrunner import ScriptRunContext, get_script_run_ctx
from streamlit.runtime.state import register_widget
from streamlit.type_util import (
T,
is_iterable,
)
if TYPE_CHECKING:
from collections.abc import Sequence
from streamlit.dataframe_util import OptionSequence
from streamlit.delta_generator import DeltaGenerator
from streamlit.runtime.state import (
WidgetArgs,
WidgetCallback,
WidgetKwargs,
)
class MultiSelectSerde(Generic[T]):
options: Sequence[T]
formatted_options: list[str]
formatted_option_to_option_index: dict[str, int]
default_options_indices: list[int]
def __init__(
self,
options: Sequence[T],
*,
formatted_options: list[str],
formatted_option_to_option_index: dict[str, int],
default_options_indices: list[int] | None = None,
) -> None:
"""Initialize the MultiSelectSerde.
We do not store an option_to_formatted_option mapping because the generic
options might not be hashable, which would raise a RuntimeError. So we do
two lookups: option -> index -> formatted_option[index].
Parameters
----------
options : Sequence[T]
The sequence of selectable options.
formatted_options : list[str]
The string representations of each option. The formatted_options correspond
to the options sequence by index.
formatted_option_to_option_index : dict[str, int]
A mapping from formatted option strings to their corresponding indices in
the options sequence.
default_option_index : int or None, optional
The index of the default option to use when no selection is made.
If None, no default option is selected.
"""
self.options = options
self.formatted_options = formatted_options
self.formatted_option_to_option_index = formatted_option_to_option_index
self.default_options_indices = default_options_indices or []
def serialize(self, value: list[T | str] | list[T]) -> list[str]:
converted_value = convert_anything_to_list(value)
values: list[str] = []
for v in converted_value:
try:
option_index = self.options.index(v)
values.append(self.formatted_options[option_index])
except ValueError: # noqa: PERF203
# at this point we know that v is a string, otherwise
# it would have been found in the options
values.append(cast("str", v))
return values
def deserialize(self, ui_value: list[str] | None) -> list[T | str] | list[T]:
if ui_value is None:
return [self.options[i] for i in self.default_options_indices]
values: list[T | str] = []
for v in ui_value:
try:
option_index = self.formatted_options.index(v)
values.append(self.options[option_index])
except ValueError: # noqa: PERF203
values.append(v)
return values
def _get_default_count(default: Sequence[Any] | Any | None) -> int:
if default is None:
return 0
if not is_iterable(default):
return 1
return len(cast("Sequence[Any]", default))
def _check_max_selections(
selections: Sequence[Any] | Any | None, max_selections: int | None
) -> None:
if max_selections is None:
return
default_count = _get_default_count(selections)
if default_count > max_selections:
raise StreamlitSelectionCountExceedsMaxError(
current_selections_count=default_count, max_selections_count=max_selections
)
class MultiSelectMixin:
@overload
def multiselect(
self,
label: str,
options: OptionSequence[T],
default: Any | None = None,
format_func: Callable[[Any], str] = str,
key: Key | None = None,
help: str | None = None,
on_change: WidgetCallback | None = None,
args: WidgetArgs | None = None,
kwargs: WidgetKwargs | None = None,
*, # keyword-only arguments:
max_selections: int | None = None,
placeholder: str | None = None,
disabled: bool = False,
label_visibility: LabelVisibility = "visible",
accept_new_options: Literal[False] = False,
width: WidthWithoutContent = "stretch",
) -> list[T]: ...
@overload
def multiselect(
self,
label: str,
options: OptionSequence[T],
default: Any | None = None,
format_func: Callable[[Any], str] = str,
key: Key | None = None,
help: str | None = None,
on_change: WidgetCallback | None = None,
args: WidgetArgs | None = None,
kwargs: WidgetKwargs | None = None,
*, # keyword-only arguments:
max_selections: int | None = None,
placeholder: str | None = None,
disabled: bool = False,
label_visibility: LabelVisibility = "visible",
accept_new_options: Literal[True] = True,
width: WidthWithoutContent = "stretch",
) -> list[T | str]: ...
@overload
def multiselect(
self,
label: str,
options: OptionSequence[T],
default: Any | None = None,
format_func: Callable[[Any], str] = str,
key: Key | None = None,
help: str | None = None,
on_change: WidgetCallback | None = None,
args: WidgetArgs | None = None,
kwargs: WidgetKwargs | None = None,
*, # keyword-only arguments:
max_selections: int | None = None,
placeholder: str | None = None,
disabled: bool = False,
label_visibility: LabelVisibility = "visible",
accept_new_options: bool = False,
width: WidthWithoutContent = "stretch",
) -> list[T] | list[T | str]: ...
@gather_metrics("multiselect")
def multiselect(
self,
label: str,
options: OptionSequence[T],
default: Any | None = None,
format_func: Callable[[Any], str] = str,
key: Key | None = None,
help: str | None = None,
on_change: WidgetCallback | None = None,
args: WidgetArgs | None = None,
kwargs: WidgetKwargs | None = None,
*, # keyword-only arguments:
max_selections: int | None = None,
placeholder: str | None = None,
disabled: bool = False,
label_visibility: LabelVisibility = "visible",
accept_new_options: Literal[False, True] | bool = False,
width: WidthWithoutContent = "stretch",
) -> list[T] | list[T | str]:
r"""Display a multiselect widget.
The multiselect widget starts as empty.
Parameters
----------
label: str
A short label explaining to the user what this select widget is for.
The label can optionally contain GitHub-flavored Markdown of the
following types: Bold, Italics, Strikethroughs, Inline Code, Links,
and Images. Images display like icons, with a max height equal to
the font height.
Unsupported Markdown 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"``.
See the ``body`` parameter of |st.markdown|_ for additional,
supported Markdown directives.
For accessibility reasons, you should never set an empty label, but
you can hide it with ``label_visibility`` if needed. In the future,
we may disallow empty labels by raising an exception.
.. |st.markdown| replace:: ``st.markdown``
.. _st.markdown: https://docs.streamlit.io/develop/api-reference/text/st.markdown
options: Iterable
Labels for the select options in an ``Iterable``. This can be a
``list``, ``set``, or anything supported by ``st.dataframe``. If
``options`` is dataframe-like, the first column will be used. Each
label will be cast to ``str`` internally by default.
default: Iterable of V, V, or None
List of default values. Can also be a single value.
format_func: function
Function to modify the display of the 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 command.
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. No two widgets may have the same key.
help: str or None
A tooltip that gets displayed next to the widget label. Streamlit
only displays the tooltip when ``label_visibility="visible"``. If
this is ``None`` (default), no tooltip is displayed.
The tooltip can optionally contain GitHub-flavored Markdown,
including the Markdown directives described in the ``body``
parameter of ``st.markdown``.
on_change: callable
An optional callback invoked when this widget'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.
max_selections: int
The max selections that can be selected at a time.
placeholder: str or None
A string to display when no options are selected.
If this is ``None`` (default), the widget displays placeholder text
based on the widget's configuration:
- "Choose options" is displayed when options are available and
``accept_new_options=False``.
- "Choose or add options" is displayed when options are available
and ``accept_new_options=True``.
- "Add options" is displayed when no options are available and
``accept_new_options=True``.
- "No options to select" is displayed when no options are available
and ``accept_new_options=False``. The widget is also disabled in
this case.
disabled: bool
An optional boolean that disables the multiselect widget if set
to ``True``. The default is ``False``.
label_visibility: "visible", "hidden", or "collapsed"
The visibility of the label. The default is ``"visible"``. If this
is ``"hidden"``, Streamlit displays an empty spacer instead of the
label, which can help keep the widget aligned with other widgets.
If this is ``"collapsed"``, Streamlit displays no label or spacer.
accept_new_options: bool
Whether the user can add selections that aren't included in ``options``.
If this is ``False`` (default), the user can only select from the
items in ``options``. If this is ``True``, the user can enter new
items that don't exist in ``options``.
When a user enters and selects a new item, it is included in the
widget's returned list as a string. The new item is not added to
the widget's drop-down menu. Streamlit will use a case-insensitive
match from ``options`` before adding a new item, and a new item
can't be added if a case-insensitive match is already selected. The
``max_selections`` argument is still enforced.
width : "stretch" or int
The width of the multiselect widget. This can be one of the
following:
- ``"stretch"`` (default): The width of the widget matches the
width of the parent container.
- An integer specifying the width in pixels: The widget has a
fixed width. If the specified width is greater than the width of
the parent container, the width of the widget matches the width
of the parent container.
Returns
-------
list
A list with the selected options
Examples
--------
**Example 1: Use a basic multiselect widget**
You can declare one or more initial selections with the ``default``
parameter.
>>> import streamlit as st
>>>
>>> options = st.multiselect(
... "What are your favorite colors?",
... ["Green", "Yellow", "Red", "Blue"],
... default=["Yellow", "Red"],
... )
>>>
>>> st.write("You selected:", options)
.. output::
https://doc-multiselect.streamlit.app/
height: 350px
**Example 2: Let users to add new options**
To allow users to enter and select new options that aren't included in
the ``options`` list, use the ``accept_new_options`` parameter. To
prevent users from adding an unbounded number of new options, use the
``max_selections`` parameter.
>>> import streamlit as st
>>>
>>> options = st.multiselect(
... "What are your favorite cat names?",
... ["Jellybeans", "Fish Biscuit", "Madam President"],
... max_selections=5,
... accept_new_options=True,
... )
>>>
>>> st.write("You selected:", options)
.. output::
https://doc-multiselect-accept-new-options.streamlit.app/
height: 350px
"""
# Convert empty string to single space to distinguish from None:
# - None (default) → "" → Frontend shows contextual placeholders
# - "" (explicit empty) → " " → Frontend shows empty placeholder
# - "Custom" → "Custom" → Frontend shows custom placeholder
if placeholder == "":
placeholder = " "
ctx = get_script_run_ctx()
return self._multiselect(
label=label,
options=options,
default=default,
format_func=format_func,
key=key,
help=help,
on_change=on_change,
args=args,
kwargs=kwargs,
max_selections=max_selections,
placeholder=placeholder,
disabled=disabled,
label_visibility=label_visibility,
accept_new_options=accept_new_options,
width=width,
ctx=ctx,
)
def _multiselect(
self,
label: str,
options: OptionSequence[T],
default: Any | None = None,
format_func: Callable[[Any], str] = str,
key: Key | None = None,
help: str | None = None,
on_change: WidgetCallback | None = None,
args: WidgetArgs | None = None,
kwargs: WidgetKwargs | None = None,
*, # keyword-only arguments:
max_selections: int | None = None,
placeholder: str | None = None,
disabled: bool = False,
label_visibility: LabelVisibility = "visible",
accept_new_options: bool = False,
width: WidthWithoutContent = "stretch",
ctx: ScriptRunContext | None = None,
) -> list[T] | list[T | str]:
key = to_key(key)
widget_name = "multiselect"
check_widget_policies(
self.dg,
key,
on_change,
default_value=default,
)
maybe_raise_label_warnings(label, label_visibility)
indexable_options = convert_to_sequence_and_check_comparable(options)
formatted_options, formatted_option_to_option_index = create_mappings(
indexable_options, format_func
)
default_values = get_default_indices(indexable_options, default)
# Convert empty string to single space to distinguish from None:
# - None (default) → "" → Frontend shows contextual placeholders
# - "" (explicit empty) → " " → Frontend shows empty placeholder
# - "Custom" → "Custom" → Frontend shows custom placeholder
if placeholder == "":
placeholder = " "
form_id = current_form_id(self.dg)
element_id = compute_and_register_element_id(
widget_name,
user_key=key,
form_id=form_id,
dg=self.dg,
label=label,
options=formatted_options,
default=default_values,
help=help,
max_selections=max_selections,
placeholder=placeholder,
accept_new_options=accept_new_options,
width=width,
)
proto = MultiSelectProto()
proto.id = element_id
proto.default[:] = default_values
proto.form_id = form_id
proto.disabled = disabled
proto.label = label
proto.max_selections = max_selections or 0
proto.placeholder = placeholder or ""
proto.label_visibility.value = get_label_visibility_proto_value(
label_visibility
)
proto.options[:] = formatted_options
if help is not None:
proto.help = dedent(help)
proto.accept_new_options = accept_new_options
serde = MultiSelectSerde(
indexable_options,
formatted_options=formatted_options,
formatted_option_to_option_index=formatted_option_to_option_index,
default_options_indices=default_values,
)
widget_state = register_widget(
proto.id,
on_change_handler=on_change,
args=args,
kwargs=kwargs,
deserializer=serde.deserialize,
serializer=serde.serialize,
ctx=ctx,
value_type="string_array_value",
)
_check_max_selections(widget_state.value, max_selections)
widget_state = maybe_coerce_enum_sequence(
widget_state, options, indexable_options
)
if widget_state.value_changed:
proto.raw_values[:] = serde.serialize(widget_state.value)
proto.set_value = True
validate_width(width)
layout_config = LayoutConfig(width=width)
if ctx:
save_for_app_testing(ctx, element_id, format_func)
self.dg._enqueue(widget_name, proto, layout_config=layout_config)
return widget_state.value
@property
def dg(self) -> DeltaGenerator:
"""Get our DeltaGenerator."""
return cast("DeltaGenerator", self)