Reactive programming- ex

import random

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

app_ui = ui.page_fluid(
    ui.markdown(
        f"""
        3가지 방법을 통해 `@reactive.event()`를 사용하여, 실행을 제한하는 방법을 보여주는 예제\\
        아래 방법 모두 0.5초마다 업데이트되는 임의의 값에 따라 결과가 달라진다.
        1)  `@render` 함수,
        2) `@reactive.calc`, 또는
        3) `@reactive.effect`.

        버튼이 클릭될 때만 출력이 업데이트되고,
        임의의 값은 {ui.output_ui("my_random_num", inline=True)}이다.
        """
    ),
    ui.row(
        ui.column(3,
            ui.input_action_button("btn_1_out", "(1) Update number"),
            ui.output_text("out_out"),
        ),
        ui.column(3,
            ui.input_action_button("btn_1_ui", "(1-1) number"),
            ui.output_ui("out_ui"),
        ),
        ui.column(3,
            ui.input_action_button("btn_2_calc", "(2) Show 1/number"),
            ui.output_text("out_calc"),
        ),
        ui.column(3,
            ui.input_action_button("btn_3_effect", "(3) Log number"),
            ui.div(id="out_effect"),
        ),

    ),
)

def server(input: Inputs, output: Outputs, session: Session):
    # 매 .5초마다 random number 생성
    rct_curr_val = reactive.value(7)
    @reactive.effect
    def _():
        reactive.invalidate_later(0.5)
        rct_curr_val.set(random.randint(0, 1000))

    @render.ui
    def my_random_num():
        return rct_curr_val.get()

    ### ------ 1. @render ------
    @render.text
    @reactive.event(input.btn_1_out)
    def out_out():
        print(f"input.btn_1_out: {input.btn_1_out()}")
        return str(rct_curr_val.get())

    @render.ui
    @reactive.event(input.btn_1_ui)
    def out_ui():
        return ui.p("current number is ", rct_curr_val.get())

    ### ------ 2. @calc ------
    @reactive.calc
    @reactive.event(input.btn_2_calc)
    def calc():
        print("Calculating 1 / rct_curr_val.get()")
        return 1 / rct_curr_val.get()

    @render.text
    def out_calc():
        return str(calc())

    ### ------ 3. effect ------
    @reactive.effect
    @reactive.event(input.btn_3_effect)
    def _():
        ui.insert_ui(
            ui.p("current number is ", rct_curr_val.get()),
            selector="#out_effect",
        )

app = App(app_ui, server)