Outline

• A minimum examples
• How to deploy the Python Shiny app
• Basics on UI and Server
• More on this topic next week…

Python Shiny application gallery

https://shiny.posit.co/py/gallery/

A minimum examples

reference: https://shiny.posit.co/py/docs/install.html

1. Open Anaconda,
   • create/select an environment
     • recommend a new environment
   • create a folder and go into the folder
2. In Python terminal, install the required packages

pip install --upgrade pip wheel
pip install shiny
pip install --upgrade shiny htmltools

3. In Python terminal, create a Python Shiny using the default

cd your_working_directory ## go to your working directory
shiny create . ## This will create a basic Shiny application in the current directory, in a file named app.py.
shiny run --reload

4. If the web application doesn’t show up, copy the URL into your browser (e.g., http://127.0.0.1:8000/)

Deploy on shinyapps.io

follow the instruction on https://www.shinyapps.io/admin/#/dashboard

1. INSTALL RSCONNECT-PYTHON

pip install rsconnect-python

2. AUTHORIZE ACCOUNT

• replace biostatisticscomputing with your account
• replace token with your token
• replace with your secret

rsconnect add \
      --account biostatisticscomputing \
      --name biostatisticscomputing \
      --token 9C753A57C8E5CE5E00F92F109C0B172B \
      --secret <SECRET>

3. DEPLOY

rsconnect deploy shiny path/to/your/app --name biostatisticscomputing --title your-app-name

A minimum example

from shiny import App, ui

# Part 1: ui ----
app_ui = ui.page_fluid(
    "Hello, world!",
)

# Part 2: server ----
def server(input, output, session):
    ...

# Combine into a shiny app.
# Note that the variable must be "app".
app = App(app_ui, server)

Adding UI inputs and outputs

from shiny import App, ui

app_ui = ui.page_fluid(
    ui.input_slider("n", "Choose a number n:", 0, 100, 40),
    ui.output_text_verbatim("txt")
)

def server(input, output, session):
    pass

app = App(app_ui, server)

Adding server logic

• define a function named txt, whose output shows up in the UI’s output_text_verbatim(“txt”).
• decorate it with @render.text, to say the result is text (and not, e.g., an image).
• decorate it with @output, to say the result should be displayed on the web page.

from shiny import ui, render, App

app_ui = ui.page_fluid(
    ui.input_slider("n", "N", 0, 100, 40),
    ui.output_text_verbatim("txt"),
)

def server(input, output, session):
    @output
    @render.text
    def txt():
        return f"n*2 is {input.n() * 2}"

# This is a shiny.App object. It must be named `app`.
app = App(app_ui, server)

Reactive flow

More on this topic next week

Will follow close to this tutorial:

• https://shiny.posit.co/py/docs/overview.html

References:

• https://shiny.posit.co/py/docs/overview.html
• https://shiny.posit.co/py/docs/install.html