Dropdown

class marimo.ui.dropdown(options: Sequence[str] | dict[str, Any], value: str | None = None, allow_select_none: bool | None = None, *, label: str = '', on_change: Callable[[Any], None] | None = None, full_width: bool = False)

A dropdown menu.

Example.

dropdown = mo.ui.dropdown(
    options=["a", "b", "c"], value="a", label="choose one"
)

dropdown = mo.ui.dropdown(
    options={"one": 1, "two": 2, "three": 3},
    value="one",
    label="pick a number",
)

Attributes.

• value: the selected value, or None if no selection

• options: a dict mapping option name to option value

• selected_key: the selected option’s key, or None if no selection

Initialization Args.

• options: sequence of text options, or dict mapping option name to option value

• value: default option name

• allow_select_none: whether to include special option ("--") for a None value; when None, defaults to True when value is None

• label: text label for the element

• on_change: optional callback to run when this element’s value changes

• full_width: whether the input should take up the full width of its container

Public methods

Inherited from UIElement

form([label, bordered, loading, ...])

Create a submittable form out of this UIElement.

Inherited from Html

batch(**elements)	Convert an HTML object with templated text into a UI element.
center()	Center an item.
right()	Right-justify.
left()	Left-justify.
callout([kind])	Create a callout containing this HTML element.
style(style)	Wrap an object in a styled container.

Public Data Attributes:

selected_key

The selected option’s key, or None if no selection.

Inherited from UIElement

value

The element’s current value.

Inherited from Html

text	A string of HTML representing this element.

---

property selected_key: str | None

The selected option’s key, or None if no selection.