rggplot2

Worldphones shiny app not showing ggplot barplot

I am trying to build a shiny app with the worldphones dataset but the ggplot barchart is not showing.

I am using two separate files, i.e ui.R and server.R

Below you can find my code. Could you please help me with it?

library(datasets)
library(tidyverse)
library(shiny)

# Use a fluid Bootstrap layout
fluidPage(    
  
  # Give the page a title
  titlePanel("Telephones by country"),
  
  # Generate a row with a sidebar
  sidebarLayout(      
    
    # Define the sidebar with one input
    sidebarPanel(
      selectInput("Country", "Country:", 
                  choices=colnames(WorldPhones)),
    ),
    
    # Create a spot for the barplot
    mainPanel(
      plotOutput("phonePlot")  
    )
  )
)


library(datasets)
library(tidyverse)
library(shiny)
library(ggplot2)

# Define a server for the Shiny app
function(input, output) {
  
  # Fill in the spot we created for a plot
  output$phonePlot <- renderPlot({
    
    # Render a barplot
    WorldPhones %>%
      as.data.frame() %>%
      rownames_to_column("Year") %>%
      pivot_longer(cols = -Year, names_to = "Country", values_to = "Users") %>%
      ggplot(aes(x = Year, y = input$Users)) +
      geom_col() +
      theme_minimal()
  })
}

enter image description here

Solution

  • The aes() call in ggplot() references input$Users, but input$Users doesn't exist. Instead, you should filter the dataset based on the selected input$Country which does exist and use it to plot Users.

    library(datasets)
library(tidyverse)
library(shiny)
library(ggplot2)

# Use a fluid Bootstrap layout
ui <- fluidPage(
  # Give the page a title
  titlePanel("Telephones by Country"),
  
  # Generate a row with a sidebar
  sidebarLayout(
    # Define the sidebar with one input
    sidebarPanel(
      selectInput("Country", "Country:", choices = colnames(WorldPhones)),
    ), 
    # Create a spot for the barplot
    mainPanel(plotOutput("phonePlot"))
  )
)

# Define a server for the Shiny app
server <- function(input, output) {
  
  # Fill in the spot we created for a plot
  output$phonePlot <- renderPlot({
    
    # Render a barplot
    WorldPhones %>%
      as.data.frame() %>%
      rownames_to_column("Year") %>%
      pivot_longer(cols = -Year, names_to = "Country", values_to = "Users") %>%
      filter(Country == input$Country) %>%  # Filter for selected country
      ggplot(aes(x = Year, y = Users)) +   # Use Users as the y value
      geom_col(fill = "steelblue") +
      labs(
        title = paste("Telephones in", input$Country),
        x = "Year",
        y = "Number of Telephones"
      ) +
      theme_minimal()
  })
}

# Run the Shiny app
shinyApp(ui, server)

    out