# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022) # # 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 dataclasses import dataclass from textwrap import dedent from typing import TYPE_CHECKING, Any, Callable, Generic, Optional, Sequence, cast from streamlit.elements.form import current_form_id from streamlit.elements.utils import ( check_callback_rules, check_session_state_rules, get_label_visibility_proto_value, ) from streamlit.errors import StreamlitAPIException from streamlit.proto.Selectbox_pb2 import Selectbox as SelectboxProto 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, register_widget, ) from streamlit.type_util import ( Key, LabelVisibility, OptionSequence, T, ensure_indexable, maybe_raise_label_warnings, to_key, ) from streamlit.util import index_ if TYPE_CHECKING: from streamlit.delta_generator import DeltaGenerator @dataclass class SelectboxSerde(Generic[T]): options: Sequence[T] index: int def serialize(self, v: object) -> int: if len(self.options) == 0: return 0 return index_(self.options, v) def deserialize( self, ui_value: Optional[int], widget_id: str = "", ) -> Optional[T]: idx: int = ui_value if ui_value is not None else self.index return self.options[idx] if len(self.options) > 0 else None class SelectboxMixin: @gather_metrics("selectbox") def selectbox( self, label: str, options: OptionSequence[T], index: int = 0, format_func: Callable[[Any], Any] = str, key: Optional[Key] = None, help: Optional[str] = None, on_change: Optional[WidgetCallback] = None, args: Optional[WidgetArgs] = None, kwargs: Optional[WidgetKwargs] = None, *, # keyword-only arguments: disabled: bool = False, label_visibility: LabelVisibility = "visible", ) -> Optional[T]: r"""Display a select widget. Parameters ---------- label : str A short label explaining to the user what this select widget 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. 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 : Sequence, numpy.ndarray, pandas.Series, pandas.DataFrame, or pandas.Index Labels for the select options. This will be cast to str internally by default. For pandas.DataFrame, the first column is selected. index : int The index of the preselected option on first render. format_func : function Function to modify the display of the labels. It receives the option as an argument and its output will be cast to str. 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 selectbox. on_change : callable An optional callback invoked when this selectbox'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 selectbox if set to True. The default is False. This argument can only be supplied by keyword. label_visibility : "visible" or "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". This argument can only be supplied by keyword. Returns ------- any The selected option Example ------- >>> import streamlit as st >>> >>> option = st.selectbox( ... 'How would you like to be contacted?', ... ('Email', 'Home phone', 'Mobile phone')) >>> >>> st.write('You selected:', option) .. output:: https://doc-selectbox.streamlitapp.com/ height: 320px """ ctx = get_script_run_ctx() return self._selectbox( label=label, options=options, index=index, format_func=format_func, key=key, help=help, on_change=on_change, args=args, kwargs=kwargs, disabled=disabled, label_visibility=label_visibility, ctx=ctx, ) def _selectbox( self, label: str, options: OptionSequence[T], index: int = 0, format_func: Callable[[Any], Any] = str, key: Optional[Key] = None, help: Optional[str] = None, on_change: Optional[WidgetCallback] = None, args: Optional[WidgetArgs] = None, kwargs: Optional[WidgetKwargs] = None, *, # keyword-only arguments: disabled: bool = False, label_visibility: LabelVisibility = "visible", ctx: Optional[ScriptRunContext] = None, ) -> Optional[T]: key = to_key(key) 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) if not isinstance(index, int): raise StreamlitAPIException( "Selectbox Value has invalid type: %s" % type(index).__name__ ) if len(opt) > 0 and not 0 <= index < len(opt): raise StreamlitAPIException( "Selectbox index must be between 0 and length of options" ) selectbox_proto = SelectboxProto() selectbox_proto.label = label selectbox_proto.default = index selectbox_proto.options[:] = [str(format_func(option)) for option in opt] selectbox_proto.form_id = current_form_id(self.dg) if help is not None: selectbox_proto.help = dedent(help) serde = SelectboxSerde(opt, index) widget_state = register_widget( "selectbox", selectbox_proto, user_key=key, on_change_handler=on_change, args=args, kwargs=kwargs, deserializer=serde.deserialize, serializer=serde.serialize, ctx=ctx, ) # This needs to be done after register_widget because we don't want # the following proto fields to affect a widget's ID. selectbox_proto.disabled = disabled selectbox_proto.label_visibility.value = get_label_visibility_proto_value( label_visibility ) if widget_state.value_changed: selectbox_proto.value = serde.serialize(widget_state.value) selectbox_proto.set_value = True self.dg._enqueue("selectbox", selectbox_proto) return widget_state.value @property def dg(self) -> "DeltaGenerator": """Get our DeltaGenerator.""" return cast("DeltaGenerator", self)