shiny multiple input done

library(shiny)
df <- data.frame(
   brand=c("a","a","a","a","a","a","b","b","b","b","b","c","c","c","c","c"),
   model=c("a21","a21","a21","a21","a31","a31","b55","b55","b56","b56","b56","c33","c34","c34","c33","c34"),
   tax=c("y","x","y","x","x","y","x","x","x","y","y","x","y","x","y","y"),
   seller=c("B","B","B","C","C","D","A","D","B","C","C","B","A","C","C","B"),
   price=c(1000,1100,1500,1400,1200,1300,2000,2200,1900,1800,1700,800,900,850,950,880), stringsAsFactors = F)
app = shinyApp(
   ui = shinyUI(fluidPage(
      titlePanel("hirearchy data group"),
      sidebarLayout(
         sidebarPanel(
            selectInput("brand",label="choice the brand",choices=c("all", sort(unique(df$brand)))),
            selectInput("model",label="choice the model",choices=c("all",sort(unique(df$model)))),
            selectInput("tax",label="choice the tax",choices=c("all", sort(unique(df$tax)))),
            selectInput("seller",label="choice the seller",choices=c("all", sort(unique(df$seller))))
         ),
         mainPanel(dataTableOutput("table"))
      ))),
   server = function(input, output, session) {
      vals = reactiveValues()
      vals$df = df
      vals$brand = "all"
      vals$model="all"
      vals$tax = "all"
      vals$seller = "all"
      updateInput_f = function(panel_name){
         choice = c("all", sort(unique(vals$df[[panel_name]]))) #[[]]變成字串
         updateSelectInput(session, panel_name, choice = choice, selected = input[[panel_name]])
      }
      updateDF_f = function(){
         vals$df = df
         if (vals$brand != "all")
            vals$df = vals$df[vals$df$brand == vals$brand,]
         if (vals$model != "all")
            vals$df = vals$df[vals$df$model == vals$model,]
         if (vals$tax != "all")
            vals$df = vals$df[vals$df$tax == vals$tax,]
         if (vals$seller != "all")
            vals$df = vals$df[vals$df$seller == vals$seller,]
      }
      brand = observe({
         input$brand
         isolate({
            vals$brand = ifelse(input$brand == "all", "all", input$brand)
            updateDF_f()
            #updateInput_f("brand")
            updateInput_f("model")
            updateInput_f("tax")
            updateInput_f("seller")
         })
      })
      model = observe({
         input$model
         isolate({
            vals$model = ifelse(input$brand == "all", "all", input$model)
            updateDF_f()
            updateInput_f("brand")
            #updateInput_f("model")
            updateInput_f("tax")
            updateInput_f("seller")
         })
      })
      tax = observe({
         input$tax
         isolate({
            vals$tax = ifelse(input$tax == "all", "all", input$tax)
            updateDF_f()
            updateInput_f("brand")
            updateInput_f("model")
            #updateInput_f("tax")
            updateInput_f("seller")
         })
      })
      seller = observe({
         input$seller
         isolate({
            vals$seller = ifelse(input$seller == "all", "all", input$seller)
            updateDF_f()
            updateInput_f("brand")
            updateInput_f("model")
            updateInput_f("tax")
            #updateInput_f("seller")
         })
      })

      output$table = renderDataTable({vals$df})
   }
)
runApp(app)