How to change the value of an ui.input element based on another input?

Question

Is it possible to change the default value of an py-shiny ui.input element based on another input? In the example if I tick "Use uppercase letters" the value should switch from "example text" to "EXAMPLE TEXT".

from shiny import App, Inputs, Outputs, Session, render, ui

app_ui = ui.page_fluid(
    ui.input_checkbox("Uppercase", "Use uppercase letters", False),
    ui.input_text("caption", "Caption:", value="example text"),
    ui.output_text_verbatim("value"),
)


def server(input: Inputs, output: Outputs, session: Session):
    @render.text
    def value():
        return input.caption()


app = App(app_ui, server)

Answer 1

You can define an reactive.effect containing an ui.update_text which updates the value depending on input.Uppercase():

from shiny import App, Inputs, Outputs, Session, render, ui, reactive

app_ui = ui.page_fluid(
    ui.input_checkbox("Uppercase", "Use uppercase letters", False),
    ui.input_text("caption", "Caption:"),
    ui.output_text_verbatim("value"),
)

def server(input: Inputs, output: Outputs, session: Session):
    @render.text
    def value():
        return input.caption()

    @reactive.effect
    def _():
        ui.update_text(
            "caption",
            value="EXAMPLE TEXT" if input.Uppercase() else "example text"
        )

app = App(app_ui, server)