Shiny basics for interactive apps in R Programming - Mini Project: Build & Apply

Shiny basics for interactive apps

📖 Scenario: You want to create a simple interactive web app using Shiny in R. This app will let users enter a number and see its square displayed immediately.

🎯 Goal: Build a Shiny app that takes a number input from the user and shows the squared value as output.

📋 What You'll Learn

Create a UI with a numeric input called num

Create a server function that calculates the square of num

Display the squared value in the UI using textOutput

Use renderText in the server to update the output dynamically

💡 Why This Matters

🌍 Real World

Shiny apps let you create interactive dashboards and tools for data analysis that anyone can use in a web browser.

💼 Career

Many data science and analytics jobs require building Shiny apps to share insights and reports interactively.

1

Set up the UI with a numeric input

Write code to create a Shiny UI object called ui using fluidPage() that contains a numeric input with inputId num, label Enter a number:, and default value 1.

R Programming

library(shiny)

# Create UI with numeric input
# Your code here

Need a hint?

Use numericInput() inside fluidPage() to create the input.

2

Add a text output to the UI

Add a textOutput with outputId result inside the existing fluidPage() UI object called ui.

R Programming

library(shiny)

ui <- fluidPage(
  numericInput(inputId = "num", label = "Enter a number:", value = 1),
  # Add textOutput here
  
  # Your code here
)

Need a hint?

Use textOutput() to show text output in the UI.

3

Create the server function to calculate square

Write a server function called server with arguments input and output. Inside it, assign output$result to renderText() that returns the square of input$num.

R Programming

library(shiny)

ui <- fluidPage(
  numericInput(inputId = "num", label = "Enter a number:", value = 1),
  textOutput(outputId = "result")
)

# Create server function

# Your code here

Need a hint?

Use renderText() to create reactive text output that depends on input$num.

4

Run the Shiny app

Write code to run the Shiny app by calling shinyApp() with the ui and server objects.

R Programming

library(shiny)

ui <- fluidPage(
  numericInput(inputId = "num", label = "Enter a number:", value = 1),
  textOutput(outputId = "result")
)

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

# Run the app
# Your code here

Need a hint?

Use shinyApp() to launch the app with your UI and server.