shiny.ui.update_select#

shiny.ui.update_select(id, *, label=None, choices=None, selected=None, session=None)#

Change the value of a select input on the client.

Parameters
  • id (str) – An input id.

  • label (Optional[str]) – An input label.

  • choices (Union[List[str], Tuple[str, …], Mapping[str, Union[Tagifiable, Tag, MetadataNode, str, TagList, float, None, Dict[str, Union[str, float, bool, None]], Sequence[Union[Tagifiable, Tag, MetadataNode, str, TagList, float, None, Dict[str, Union[str, float, bool, None]], Sequence[ForwardRef]]]]], Mapping[str, Mapping[str, Union[Tagifiable, Tag, MetadataNode, str, TagList, float, None, Dict[str, Union[str, float, bool, None]], Sequence[Union[Tagifiable, Tag, MetadataNode, str, TagList, float, None, Dict[str, Union[str, float, bool, None]], Sequence[ForwardRef]]]]]], None]) – Either a list of choices or a dictionary mapping choice values to labels. Note that if a dictionary is provided, the keys are used as the (input) values so that the dictionary values can hold HTML labels. A dictionary of dictionaries is also supported, and in that case, the top-level keys are treated as <optgroup> labels.

  • selected (Union[str, List[str], None]) – The values that should be initially selected, if any.

  • session (Optional[Session]) – A Session instance. If not provided, it is inferred via get_current_session().

Note

The input updater functions send a message to the client, telling it to change the settings of an input object. The messages are collected and sent after all the observers (including outputs) have finished running.

The syntax of these functions is similar to the functions that created the inputs in the first place. For example, input_numeric() and update_numeric() take a similar set of arguments.

Any arguments with None values will be ignored; they will not result in any changes to the input object on the client.

For update_radio_buttons(), update_checkbox_group(), and update_select(), the set of choices can be cleared by using choices=[]. Similarly, for these inputs, the selected item can be cleared by using selected=[].

Example

#| standalone: true
#| components: [editor, viewer]
#| layout: vertical
#| viewerHeight: 400
from shiny import *

app_ui = ui.page_fluid(
    ui.tags.p("The checkbox group controls the select input"),
    ui.input_checkbox_group(
        "inCheckboxGroup", "Input checkbox", ["Item A", "Item B", "Item C"]
    ),
    ui.input_select("inSelect", "Select input", ["Item A", "Item B", "Item C"]),
)

def server(input: Inputs, output: Outputs, session: Session):
    @reactive.Effect
    def _():
        x = input.inCheckboxGroup()

        # Can use [] to remove all choices
        if x is None:
            x = []
        elif isinstance(x, str):
            x = [x]

        ui.update_select(
            "inSelect",
            label="Select input label " + str(len(x)),
            choices=x,
            selected=x[len(x) - 1] if len(x) > 0 else None,
        )


app = App(app_ui, server)
Return type

None