r - Shiny not displaying ggplot data

Question

I am new to working with shiny package. I am trying to use it to display a ggplot2 graph. I get no errors with my code, however data points are not appearing on the graph. When I select the variables from ui, the axes labels changes accordingly but the data is not added to the plot.

Thank you,

Code:

ui <- fluidPage(
     sidebarLayout(
         sidebarPanel(
             selectInput(inputId = "y", 
                         label = "Y-axis:", 
                         choices = c("P-value", "P-adjust"),
                         selected = "P-adjust"),
             selectInput(inputId = "x" , 
                         label = "X-axis:", 
                         choices = c("FC", "Mean_Count_PD"),
                         selected = "FC")
                 ),
         mainPanel(plotOutput(outputId = "scatterplot"))
         ))

server <- function(input, output) 
     {
     output$scatterplot <- renderPlot({
     ggplot(data = mir, aes(input$x,input$y)) + geom_point()
     })
 }

Answer 1

The issue is that you have to tell ggplot that your inputs are names of variables in your dataset. This could be achieved e.g. by making use of the .data pronoun, i.e. instead of using input$x which is simply a string use .data[[input$x]] which tells ggplot that by input$x you mean the variable with that name in your data:

As you provided no data I could not check but this should give you the desired result:

library(shiny)
library(ggplot2)

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      selectInput(inputId = "y", 
                  label = "Y-axis:", 
                  choices = c("P-value", "P-adjust"),
                  selected = "P-adjust"),
      selectInput(inputId = "x" , 
                  label = "X-axis:", 
                  choices = c("FC", "Mean_Count_PD"),
                  selected = "FC")
    ),
    mainPanel(plotOutput(outputId = "scatterplot"))
  ))

server <- function(input, output) {
  output$scatterplot <- renderPlot({
    ggplot(data = mir, aes(.data[[input$x]], .data[[input$y]])) + geom_point()
  })
}

shinyApp(ui, server)