Shiny Apps

This topic aims to provide you with a foundation for making a shiny app. From this topic, students are anticipated to be able to:

develop the user interface of a shiny app from scratch,
develop interactivity using widgets in a shiny app,
deploy a shiny app to shinyapps.io,
create interactive Shiny R Markdown documents (embed shiny features within an Rmd file).

And possibly:

Resources

Video lecture:

Written material:

Regarding specific tasks:

For deploying shiny apps, check out https://www.shinyapps.io/
For shiny documents (= R Markdown + shiny), see Chapter 19 of Yihui’s R Markdown book.
For testing your shiny app, check out the shinytest and reactlog packages.
For further cutting down on code repetition by “functionizing” your shiny app, check out Emily Riederer’s beginner’s guide to Shiny modules for a gentle introduction and Chapter 19 of the “Mastering Shiny” book for a full treatment.

Other dashboard tools besides shiny (but not in R):

With python: plotly dash. Check out the main website, or this Medium post introducing the tool.
With javascript: D3, a tremendously powerful tool with a steep learning curve (esp. if you don’t know javascript).

We are going to be working off of a slide deck and tutorial written by Dean Attali. This should take two classes.

True or False: A shiny app, as a website, still requires an instance of R running in the background. The stat545.stat.ubc.ca website is static: it doesn’t require an active session to be running in the background.
True or False: Although it’s important to document both a shiny app and an R package, documentation is more important in R packages compared to shiny apps.
True or False: The following code ordinarily has y as 15, but using shiny::reactive() in a shiny app can have y equal 11.
```
x <- 10
y <- x + 5
x <- 1
```
True or False: Since shiny’s UI is html, we can manually write the UI by writing HTML in the HTML() function.