Question

I'm trying to allow user to select two input one for group by and another for sum in a shiny app. those input will be used to further create a summary table.

Below is the code

    library(shiny)
    library(dplyr)
    library(DT)


    df <- iris
    vchoices <- colnames(iris)
    ui <- fluidPage(h1("PLOT FOR NOW"),
                    sidebarLayout(sidebarPanel(
                      fluidPage(
                        column(10,selectInput(inputId = "group",label = "Group BY",choices = vchoices)),
                        column(10,selectInput(inputId = "sum",label = "SUM",choices = vchoices,selected = "Sepal.Length"))
                      )

                    ),
                    mainPanel(tabsetPanel(tabPanel("table",dataTableOutput("table"))
                    )))
    )

    server <- function(input,output,session){
      df1 <- reactive({df %>% group_by_(input$group) %>% summarise( fb =sum(input$sum))})

      output$table <- DT::renderDataTable(df1())



    }

    shinyApp(ui,server)

Now i have been able to use input$group with help of group_by_ function but how do I use it for sum in summaries ?

Answer 1

如评论中所述，您应该使用get()来获取输入中的值。

您也可以在group_by(get(input$group))代替group_by_(input$group)

使用它

以下是修改后的服务器功能：

   server <- function(input,output,session){
   df1 <- reactive({
   df %>% group_by_(input$group) %>% summarise( fb =sum(get(input$sum)))})

   output$table <- DT::renderDataTable(df1())

  }

希望它有所帮助！

How to use input$id value as an argument in function

1 个答案: