Shiny basics for interactive apps in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Shiny in R?

Shiny is a package in R that helps you build interactive web apps easily without needing to know web programming languages.

beginner

What are the two main parts of a Shiny app?

A Shiny app has two main parts: UI (user interface) which controls what the user sees, and server which controls how the app works behind the scenes.

beginner

What function is used to create the user interface in Shiny?

The function fluidPage() is commonly used to create a simple and responsive user interface in Shiny apps.

intermediate

How do you make a Shiny app respond to user input?

You use input widgets like sliderInput() or textInput() in the UI, and then use input$widgetId in the server to react to what the user selects or types.

beginner

What function runs a Shiny app?

The function shinyApp(ui, server) runs the app by connecting the UI and server parts together.

Which two components are essential to build a Shiny app?

A HTML and CSS

B Input and Output files

C Database and API

D UI and server

A Shiny app needs a UI to show the interface and a server to handle the logic.

What does the function sliderInput() do in Shiny?

A Creates a slider for user input

B Displays a plot

C Runs the app

D Saves data to a file

sliderInput() creates a slider widget so users can pick a number by sliding.

How do you access the value of an input widget named 'age' in the server function?

A age$input

B input$age

C output$age

D server$age

Input values are accessed using input$widgetId, so here it is input$age.

Which function is used to create a fluid and responsive UI layout in Shiny?

A fluidPage()

B fixedPage()

C runApp()

D renderUI()

fluidPage() creates a flexible layout that adjusts to screen size.

What does the server function in Shiny do?

A Starts the web server

B Defines the app's appearance

C Controls the app's logic and reactions to user input

D Stores user data permanently

The server function contains the code that reacts to user input and updates outputs.

Explain the roles of the UI and server parts in a Shiny app.

Think about what the user interacts with versus what happens behind the scenes.

Describe how you would create a simple Shiny app that takes a number input and shows it doubled.

Focus on input widgets, accessing input, and showing output.