Shiny basics for interactive apps in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a basic Shiny app UI with a title.

R Programming

ui <- fluidPage(
  [1]("My Shiny App")
)

Drag options to blanks, or click blank then click option'

AtitlePanel

BsidebarLayout

CmainPanel

DfluidRow

Attempts:

3 left

💡 Hint

Common Mistakes

Using layout functions like sidebarLayout instead of titlePanel for the title.

Confusing mainPanel with titlePanel.

The titlePanel function adds a title to the Shiny app UI.

2fill in blank

medium

Complete the code to define the server function that outputs text.

R Programming

server <- function(input, output) {
  output$text <- renderText({
    [1]("Hello, Shiny!")
  })
}

Drag options to blanks, or click blank then click option'

Aprint

BtextOutput

CrenderText

Dcat

Attempts:

3 left

💡 Hint

Common Mistakes

Using print or cat which do not work as reactive render functions.

Using textOutput which is a UI function, not server.

The renderText function is used inside the server to create text output.

3fill in blank

hard

Fix the error in the code to correctly display a numeric input in the UI.

R Programming

ui <- fluidPage(
  numericInput([1], "Enter a number:", value = 10)
)

Drag options to blanks, or click blank then click option'

AnumericInput

Bnum

Cinput$num

D"num"

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting quotes around the input ID.

Using input$num which is not valid here.

The first argument of numericInput must be a string ID in quotes.

4fill in blank

hard

Fill both blanks to create a UI with a slider input and display its value as text.

R Programming

ui <- fluidPage(
  sliderInput([1], "Choose a value:", min = 1, max = 100, value = 50),
  textOutput([2])
)

Drag options to blanks, or click blank then click option'

A"slider1"

B"sliderValue"

D"outputText"

Attempts:

3 left

💡 Hint

Common Mistakes

Using different IDs for sliderInput and textOutput.

Not quoting the IDs.

The slider input and the text output must share the same ID string to link input and output.

5fill in blank

hard

Fill all three blanks to create a Shiny app that shows the square of a numeric input.

R Programming

ui <- fluidPage(
  numericInput([1], "Number:", value = 2),
  textOutput([2])
)

server <- function(input, output) {
  output[3] <- renderText({
    input$num ^ 2
  })
}

shinyApp(ui, server)

Drag options to blanks, or click blank then click option'

A"num"

B"result"

C$result

D$num

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching IDs between UI and server.

Using incorrect syntax for output assignment.

The numeric input ID is "num". The text output ID is "result". The server output uses output$result to match the text output.