express.ui.input_select

express.ui.input_select(id, label, choices, *, selected=None, multiple=False, selectize=False, width=None, size=None, remove_button=None, options=None)

Create a select list that can be used to choose a single or multiple items from a list of values.

Parameters

id: str: An input id.
label: TagChild: An input label.
choices: SelectChoicesArg: 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: Optional[str | list[str]] = None: The values that should be initially selected, if any.
multiple: bool = False: Is selection of multiple items allowed?
selectize: bool = False: Whether to use selectize.js or not.
width: Optional[str] = None: The CSS width, e.g. ‘400px’, or ‘100%’
size: Optional[str] = None: Number of items to show in the selection box; a larger number will result in a taller box. Normally, when multiple=False, a select input will be a drop-down list, but when size is set, it will be a box instead.

Returns

Type	Description
Tag	A UI element.

Notes

Server value

If multiple=False, the server value is a string with the value of the selected item. If multiple=True, the server value is a tuple containing the values of the selected items. When multiple=True and nothing is selected, this value will be None.

Examples

#| standalone: true
#| components: [editor, viewer]
#| layout: vertical
#| viewerHeight: 400

## file: app.py
from shiny.express import input, render, ui

ui.input_select(
    "state",
    "Choose a state:",
    {
        "East Coast": {"NY": "New York", "NJ": "New Jersey", "CT": "Connecticut"},
        "West Coast": {"WA": "Washington", "OR": "Oregon", "CA": "California"},
        "Midwest": {"MN": "Minnesota", "WI": "Wisconsin", "IA": "Iowa"},
    },
)


@render.text
def value():
    return "You choose: " + str(input.state())