Changing the data frame of a ggplot graph from a dropdown menu in Shiny-CodePudding

I am trying to change the data frame that ggplot uses to render a graph given a selection of a drop down menu.

The dropdown menu works but the graph will not render.

for reference 'school' is a set of strings with the names of teams.

library(shiny)
library(shinydashboard)
library(ggplot2)

ui <- dashboardPage(
  dashboardHeader(title = "NCAA - Lorenz"),
  dashboardSidebar(
    sidebarMenu(
      menuItem("teams", tabName = "teams"),
      menuItem("Correlation", tabName = "Correlation"))),
  dashboardBody(
    tabItems(
      tabItem("teams", 
              box(plotOutput("GINI_plot"), width = 4),
              box(
                selectInput("TEAM","TEAM:",
                            c(teams)), width = 4)),
      tabItem("Correlation", 
              box(plotOutput("correlation_plot"), width = 4),
              box(
                selectInput("STATISTIC","STATISTIC:",
                            c("DRtg","Pts","ast")), width = 4))
    )
  )
)

server <- function(input, output){
  
  df <- reactive({
    get(input)
  })
  
  output$GINI_plot <- renderPlot({
    
    ggplot(data = df, aes(CUMSUM,CUMperpts))   
      geom_abline(intercept = 0, slope = 1)
    
  })
  
  output$correlation_plot <- renderPlot({
    plot(schdata[[input$STATISTIC]], schdata$gini, ylab = "Gini Coef.", xlab = "STATISTIC")
  })

}

shinyApp(ui, server)

the box in the dash board reads "Error: [object Object]" This is the error output in rstudio

Warning: Error in ggplot: `data` cannot be a function.
ℹ Have you misspelled the `data` argument in `ggplot()`
  175: <Anonymous>
  174: signalCondition
  173: signal_abort
  172: rlang::abort
  171: cli::cli_abort
  170: ggplot.function
  168: renderPlot [/home/thrash-libre/R-projects/application.R#35]
  166: func
  126: drawPlot
  112: <reactive:plotObj>
   96: drawReactive
   83: renderFunc
   82: output$GINI_plot
    1: runApp
Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.

Anything helps .

The ggplot command should just read the dataframe variable and output a graph.

I have also tried to select from a list of dataframe but that didnt work either

CodePudding user response：

Error in ggplot: `data` cannot be a function.

gives the hint: your reactive df is a function which yet has to return the dataframe. Feed the results into you ggplot like so:

ggplot(data = df(), ...)

Note the trailing parentheses which have the function df executed and return the data.

CodePudding user response：

If you assign the variable within the "renderPlot" function, you can call it within the function as a data frame.

This method is preferable since I could call a the data frame when calculating the GINI index within the Annotate function.

server <- function(input, output){
  
  output$GINI_plot <- renderPlot({
    
    datful <- fdata %>% filter(School == input$TEAM)
    
    ggplot(data = datful, aes(CUMSUM,CUMperpts))   
      geom_abline(intercept = 0, slope = 1) 
      geom_smooth() 
      xlab("Cumulative Sum of Points") 
      ylab("Cumulative Sum") 
      theme_minimal() 
      labs(title = paste(input$TEAM,"Lorenz Curve")) 
      annotate("text", x=.25, y=.82,size = 5, label = paste("GINI coeff:",signif(Gini(datful$PTS),3)))
  })
}