Introducing Gradio 5.0

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  2. Dropdown

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Dropdown

gradio.Dropdown(···)
import gradio as gr with gr.Blocks() as demo: gr.Dropdown(choices=["First Choice", "Second Choice", "Third Choice"]) demo.launch()

Description

Creates a dropdown of choices from which a single entry or multiple entries can be selected (as an input component) or displayed (as an output component).

Behavior

As input component: Passes the value of the selected dropdown choice as a str | int | float or its index as an int into the function, depending on type. Or, if multiselect is True, passes the values of the selected dropdown choices as a list of correspoding values/indices instead.

Your function should accept one of these types:
def predict(
	value: str | int | float | list[str | int | float] | list[int | None] | None
)
	...

As output component: Expects a str | int | float corresponding to the value of the dropdown entry to be selected. Or, if multiselect is True, expects a list of values corresponding to the selected dropdown entries.

Your function should return one of these types:
def predict(···) -> str | int | float | list[str | int | float] | None
	...	
	return value

Initialization

Parameters 
choices: list[str | int | float | tuple[str, str | int | float]] | None
default = None

a list of string or numeric options to choose from. An option can also be a tuple of the form (name, value), where name is the displayed name of the dropdown choice and value is the value to be passed to the function, or returned by the function.

value: str | int | float | list[str | int | float] | Callable | DefaultValue | None
default = DefaultValue()

the value selected in dropdown. If `multiselect` is true, this should be list, otherwise a single string or number. By default, the first choice is initally selected. If set to None, no value is initally selected. If a callable, the function will be called whenever the app loads to set the initial value of the component.

type: Literal['value', 'index']
default = "value"

type of value to be returned by component. "value" returns the string of the choice selected, "index" returns the index of the choice selected.

multiselect: bool | None
default = None

if True, multiple choices can be selected.

allow_custom_value: bool
default = False

if True, allows user to enter a custom value that is not in the list of choices.

max_choices: int | None
default = None

maximum number of choices that can be selected. If None, no limit is enforced.

filterable: bool
default = True

if True, user will be able to type into the dropdown and filter the choices by typing. Can only be set to False if `allow_custom_value` is False.

label: str | None
default = None

the label for this component, displayed above the component if `show_label` is `True` and is also used as the header if there are a table of examples for this component. If None and used in a `gr.Interface`, the label will be the name of the parameter this component corresponds to.

info: str | None
default = None

additional component description, appears below the label in smaller font. Supports markdown / HTML syntax.

every: Timer | float | None
default = None

continously calls `value` to recalculate it if `value` is a function (has no effect otherwise). Can provide a Timer whose tick resets `value`, or a float that provides the regular interval for the reset Timer.

inputs: Component | list[Component] | set[Component] | None
default = None

components that are used as inputs to calculate `value` if `value` is a function (has no effect otherwise). `value` is recalculated any time the inputs change.

show_label: bool | None
default = None

if True, will display label.

container: bool
default = True

if True, will place the component in a container - providing some extra padding around the border.

scale: int | None
default = None

relative size compared to adjacent Components. For example if Components A and B are in a Row, and A has scale=2, and B has scale=1, A will be twice as wide as B. Should be an integer. scale applies in Rows, and to top-level Components in Blocks where fill_height=True.

min_width: int
default = 160

minimum pixel width, will wrap if not sufficient screen space to satisfy this value. If a certain scale value results in this Component being narrower than min_width, the min_width parameter will be respected first.

interactive: bool | None
default = None

if True, choices in this dropdown will be selectable; if False, selection will be disabled. If not provided, this is inferred based on whether the component is used as an input or output.

visible: bool
default = True

if False, component will be hidden.

elem_id: str | None
default = None

an optional string that is assigned as the id of this component in the HTML DOM. Can be used for targeting CSS styles.

elem_classes: list[str] | str | None
default = None

an optional list of strings that are assigned as the classes of this component in the HTML DOM. Can be used for targeting CSS styles.

render: bool
default = True

if False, component will not be rendered in the Blocks context. Should be used if the intention is to assign event listeners now but render the component later.

key: int | str | None
default = None

Shortcuts

Class Interface String Shortcut Initialization

gradio.Dropdown

"dropdown"

 Uses default values

Demos

import gradio as gr

def sentence_builder(quantity, animal, countries, place, activity_list, morning):
    return f"""The {quantity} {animal}s from {" and ".join(countries)} went to the {place} where they {" and ".join(activity_list)} until the {"morning" if morning else "night"}"""

demo = gr.Interface(
    sentence_builder,
    [
        gr.Slider(2, 20, value=4, label="Count", info="Choose between 2 and 20"),
        gr.Dropdown(
            ["cat", "dog", "bird"], label="Animal", info="Will add more animals later!"
        ),
        gr.CheckboxGroup(["USA", "Japan", "Pakistan"], label="Countries", info="Where are they from?"),
        gr.Radio(["park", "zoo", "road"], label="Location", info="Where did they go?"),
        gr.Dropdown(
            ["ran", "swam", "ate", "slept"], value=["swam", "slept"], multiselect=True, label="Activity", info="Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed auctor, nisl eget ultricies aliquam, nunc nisl aliquet nunc, eget aliquam nisl nunc vel nisl."
        ),
        gr.Checkbox(label="Morning", info="Did they do it in the morning?"),
    ],
    "text",
    examples=[
        [2, "cat", ["Japan", "Pakistan"], "park", ["ate", "swam"], True],
        [4, "dog", ["Japan"], "zoo", ["ate", "swam"], False],
        [10, "bird", ["USA", "Pakistan"], "road", ["ran"], False],
        [8, "cat", ["Pakistan"], "zoo", ["ate"], True],
    ]
)

if __name__ == "__main__":
    demo.launch()

Event Listeners

Description

Event listeners allow you to respond to user interactions with the UI components you've defined in a Gradio Blocks app. When a user interacts with an element, such as changing a slider value or uploading an image, a function is called.

Supported Event Listeners

The Dropdown component supports the following event listeners. Each event listener takes the same parameters, which are listed in the Event Parameters table below.

Listener Description

Dropdown.change(fn, ···)

Triggered when the value of the Dropdown changes either because of user input (e.g. a user types in a textbox) OR because of a function update (e.g. an image receives a value from the output of an event trigger). See .input() for a listener that is only triggered by user input.

Dropdown.input(fn, ···)

This listener is triggered when the user changes the value of the Dropdown.

Dropdown.select(fn, ···)

Event listener for when the user selects or deselects the Dropdown. Uses event data gradio.SelectData to carry value referring to the label of the Dropdown, and selected to refer to state of the Dropdown. See EventData documentation on how to use this event data

Dropdown.focus(fn, ···)

This listener is triggered when the Dropdown is focused.

Dropdown.blur(fn, ···)

This listener is triggered when the Dropdown is unfocused/blurred.

Dropdown.key_up(fn, ···)

This listener is triggered when the user presses a key while the Dropdown is focused.

Event Parameters

Parameters 
fn: Callable | None | Literal['decorator']
default = "decorator"

the function to call when this event is triggered. Often a machine learning model's prediction function. Each parameter of the function corresponds to one input component, and the function should return a single value or a tuple of values, with each element in the tuple corresponding to one output component.

inputs: Component | BlockContext | list[Component | BlockContext] | Set[Component | BlockContext] | None
default = None

List of gradio.components to use as inputs. If the function takes no inputs, this should be an empty list.

outputs: Component | BlockContext | list[Component | BlockContext] | Set[Component | BlockContext] | None
default = None

List of gradio.components to use as outputs. If the function returns no outputs, this should be an empty list.

api_name: str | None | Literal[False]
default = None

defines how the endpoint appears in the API docs. Can be a string, None, or False. If set to a string, the endpoint will be exposed in the API docs with the given name. If None (default), the name of the function will be used as the API endpoint. If False, the endpoint will not be exposed in the API docs and downstream apps (including those that `gr.load` this app) will not be able to use this event.

scroll_to_output: bool
default = False

If True, will scroll to output component on completion

show_progress: Literal['full', 'minimal', 'hidden']
default = "full"

how to show the progress animation while event is running: "full" shows a spinner which covers the output component area as well as a runtime display in the upper right corner, "minimal" only shows the runtime display, "hidden" shows no progress animation at all

queue: bool
default = True

If True, will place the request on the queue, if the queue has been enabled. If False, will not put this event on the queue, even if the queue has been enabled. If None, will use the queue setting of the gradio app.

batch: bool
default = False

If True, then the function should process a batch of inputs, meaning that it should accept a list of input values for each parameter. The lists should be of equal length (and be up to length `max_batch_size`). The function is then *required* to return a tuple of lists (even if there is only 1 output component), with each list in the tuple corresponding to one output component.

max_batch_size: int
default = 4

Maximum number of inputs to batch together if this is called from the queue (only relevant if batch=True)

preprocess: bool
default = True

If False, will not run preprocessing of component data before running 'fn' (e.g. leaving it as a base64 string if this method is called with the `Image` component).

postprocess: bool
default = True

If False, will not run postprocessing of component data before returning 'fn' output to the browser.

cancels: dict[str, Any] | list[dict[str, Any]] | None
default = None

A list of other events to cancel when this listener is triggered. For example, setting cancels=[click_event] will cancel the click_event, where click_event is the return value of another components .click method. Functions that have not yet run (or generators that are iterating) will be cancelled, but functions that are currently running will be allowed to finish.

trigger_mode: Literal['once', 'multiple', 'always_last'] | None
default = None

If "once" (default for all events except `.change()`) would not allow any submissions while an event is pending. If set to "multiple", unlimited submissions are allowed while pending, and "always_last" (default for `.change()` and `.key_up()` events) would allow a second submission after the pending event is complete.

js: str | None
default = None

Optional frontend js method to run before running 'fn'. Input arguments for js method are values of 'inputs' and 'outputs', return should be a list of values for output components.

concurrency_limit: int | None | Literal['default']
default = "default"

If set, this is the maximum number of this event that can be running simultaneously. Can be set to None to mean no concurrency_limit (any number of this event can be running simultaneously). Set to "default" to use the default concurrency limit (defined by the `default_concurrency_limit` parameter in `Blocks.queue()`, which itself is 1 by default).

concurrency_id: str | None
default = None

If set, this is the id of the concurrency group. Events with the same concurrency_id will be limited by the lowest set concurrency_limit.

show_api: bool
default = True

whether to show this event in the "view API" page of the Gradio app, or in the ".view_api()" method of the Gradio clients. Unlike setting api_name to False, setting show_api to False will still allow downstream apps as well as the Clients to use this event. If fn is None, show_api will automatically be set to False.

time_limit: int | None
default = None 
stream_every: float
default = 0.5 
like_user_message: bool
default = False
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