反应性数据框中的闪亮-重命名因素

Question

I'm building a shiny app that queries an SQL database so the user can ggplot the data. I would like the user to be able to rename factors manually but am struggling to get going. Here is an example of what I want to do:

ui.R

library(markdown)

shinyUI(fluidPage(
  titlePanel("Reactive factor label"),
  sidebarLayout(
    sidebarPanel(

      numericInput("wafer", label = h3("Input wafer ID:"), value = NULL),

      actionButton("do", "Search wafer"),
      textInput("text", label = h3("Factor name to change"), value = ""),
      textInput("text", label = h3("New factor name"), value = ""),
      actionButton("do2", "Change name")

       ),

    mainPanel(
      verbatimTextOutput("waf"), 
      verbatimTextOutput("que"), 
      verbatimTextOutput("pos"),
      dataTableOutput(outputId="tstat")
    )
  )
)
)

server.R

# Create example data

Name <- factor(c("Happy", "New", "Year"))
Id <- 1:3

dd <- data.frame(Id, Name)

con <- dbConnect(RSQLite::SQLite(), ":memory:")
dbWriteTable(con, "dd", dd)
query <-  function(...) dbGetQuery(con, ...)

wq = data.frame()
sq = data.frame()


shinyServer(function(input, output){

  # create data frame to store reactive data set from query
  values <- reactiveValues()
  values$df <- data.frame()

  # Wait for user to search
  d <- eventReactive(input$do, { input$wafer })

  # Reactive SQL query
  a <- reactive({ paste0("Select * from dd where Id=",d()) })
  wq <- reactive({  query( a() ) })

  # Check outputs
  output$waf <- renderPrint(input$wafer)
  output$que <- renderPrint({ a() }) 
  output$pos <- renderPrint( wq()[1,1] )

  # observe d() so that data is not added until user presses action button  
  observe({
    if (!is.null(d())) {
      sq <- reactive({  query( a() ) })

      # add query to reactive data frame
      values$df <- rbind(isolate(values$df), sq())
    }
  })

  output$tstat <- renderDataTable({
    data <- values$df
  })

})

In static RI would normally use data table to rename factors ie:

DT <- data.table(df)
DT[Name=="Happy", Name:="Sad"]

But I'm not sure how to go about this with a reactiveValues ie values$df .

I have read this ( R shiny: How to get an reactive data frame updated each time pressing an actionButton without creating a new reactive data frame? ). This lead me to try this but it doesn't do anything (even no error):

observeEvent(input$do2, {
    DT <- data.table(values$df) 
    DT[Name == input$text1, Name := input$text2]
    values$df <- data.frame(values$df)

  })

Perhaps there is a way around this..maybe there is a way to use an action button to "lock in" the data as a new data frame, which can then be used to rename?

Sorry for such a long winded question. My real app is much longer and more complex. I have tried to strip it down.

Answer 1

Your approach works but there are a few issues in your app.

In ui.R , both textInput have the same id , they need to be different so you can refer to them in the server.R . In the observeEvent you posted, you refer to input$text1 and input$text2 so you should change the id of the textInputs to text1 and text2 .

In the observeEvent you posted, the last line should be values$df <- as.data.frame(DT) , otherwise it does not change anything.