eventReactive with multiple eventExpr and output depends on which eventExpr triggered the reactive function

问题

I'm working on a shiny application that has a reactive variable with multiple eventExpr triggers in an eventReactive function. Is there a way to place an if within the eventReactive function to change what the reactive variable will be? For example, the code snippet below describes what I want to do. If input$Client is changed, I want the "dat" to be multiplied by their current factor, contained in y. If the action button is hit, I would like the "dat" to be multiplied by input$Factor. Is there a way to accomplish this?

ui = fluidPage(
          selectInput(inputId = "Client", Label = "Choose Client",
                      choices = c("A", "B", "C", "D", "E")), 
          numericInput(inputId = "Factor", min = .5, max = 2, value = 1),
          actionButton(inputId = "Reprice"),
          dataTableOutput(outputId = "RepricedData")

)

server = function(input, output){
x = data.frame(rep(c("A", "B", "C", "D", "E"),20))
colnames(x) = "Client"
x$amount = runif(100, 50, 150)

y = data.frame(c("A", "B", "C", "D", "E"))
colnames(y) = "Client"
y$currentFactor = c(runif(5,.5,2))

rv = reactiveValues()

rv$repricedData = eventReactive(c(input$Client, input$Reprice), {
             dat = x$amount[which(x$Client == input$Client)]
             if(input$Client){
                dat = dat * y$currentFactor[which(y$Client == input$Client)]
                }else{
                  dat = dat * input$Factor
                }
                dat
})

output$repricedData = renderDataTable(
rv$repricedData()
  )
}

shinyApp(server = server, ui = ui)

回答1:

You could make two separate observeEvents that listen to one of both inputs. Working example:

library(shiny)
ui = fluidPage(
  selectInput(inputId = "Client", label = "Choose Client",
              choices = c("A", "B", "C", "D", "E")), 
  numericInput(inputId = "Factor", label='numeric',min = .5, max = 2, value = 1),
  actionButton(inputId = "Reprice",'reprice'),
  dataTableOutput(outputId = "repricedData")
)

server = function(input, output){
  x = data.frame(rep(c("A", "B", "C", "D", "E"),20))
  colnames(x) = "Client"
  x$amount = runif(100, 50, 150)

  y = data.frame(c("A", "B", "C", "D", "E"))
  colnames(y) = "Client"
  y$currentFactor = c(runif(5,.5,2))

  rv = reactiveVal(x)

  # Observer that listens to changes in input$Reprice
  observeEvent(input$Reprice, {
    df = rv() # Read reactiveVal
    factor = input$Factor
    df$amount[df$Client==input$Client] = df$amount[df$Client==input$Client]*factor
    rv(df) # set reactiveVal to new value
  })

  # Observer that listens to changes in input$Client
  observeEvent(input$Client, {
    df = rv() # Read reactiveVal
    factor = y$currentFactor[y$Client==input$Client]
    df$amount[df$Client==input$Client] = df$amount[df$Client==input$Client]*factor
    rv(df) # set reactiveVal to new value
  })

  output$repricedData = renderDataTable(
    rv()
  )
}

shinyApp(server = server, ui = ui)

来源：https://stackoverflow.com/questions/48914706/eventreactive-with-multiple-eventexpr-and-output-depends-on-which-eventexpr-trig

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