R编程：打印dataTableOutput时出错

Question

我正在尝试将Shiny UI SelectInput的输入发送到服务器脚本和我的server.R将从表中读取特定列并计算最小值，最大值，平均值，中值数据。我能够执行此操作并在R Console中逐行执行时获得正确的数据。无法将其作为Shiny输出发送并在Shiny UI浏览器中作为表格打印。 Server.R脚本应该从UI获取输入并仅执行该特定输入的均值，中位数。感谢您的宝贵帮助。

# ui.R
library(shiny)
library(RODBC)
library(DBI)
dbconnect <- odbcConnect("orecloud", uid="XXXX", pwd="XXXX", believeNRows=FALSE)
df <- data.frame()
df <- sqlQuery(dbconnect,"SELECT distinct cpan FROM CYTOKINE ")
shinyUI(fluidPage(
  headerPanel("ORE Cytokine Summary"),
  sidebarLayout(
    sidebarPanel(
      helpText("Please select Patient Details.."),
      selectInput("CPAN", 
                  label = "Choose patient",
                  choices = df,
                  selected = NULL),
    submitButton(text = "Submit", icon = NULL)),
    mainPanel(
         dataTableOutput("tableoutput")
    )
  )
 ))

# server.R
library(RODBC)
library(RODBC)
library(lattice)
shinyServer(
  function(input, output) {
    dbconnect <- odbcConnect("orecloud", uid="XXXX", pwd="XXXX", believeNRows=FALSE)
    df2 = reactive({
      # Created DB Connection to get details 
      input_var <- input$CPAN
      my_query <- paste("select CPAN,SCTP,MARKER,RESULT from TABLE where CPAN= ", input_var)
      sqlQuery(dbconnect,my_query)

      cleandata <- na.omit(data)
      colnames(cleandata)
      Markers <- unique(cleandata[,"MARKER"])
      #Markers
      nMarkers <- length(Markers)
      nMarkers
      Patients <- unique(cleandata[,"CPAN"])
      nPatients <- length(Patients)
      nPatients
      #Output columns defined
      output <- data.frame("Marker","Patient", "Min","Q1","Median","Mean","Q3","Max",stringsAsFactors=FALSE,check.names=FALSE)
       for (i in 1:nMarkers) {
        Mrk <- Markers[i]    
        for (j in 1:nPatients){
          Pnt <- Patients[j]
          Mrkdata  <- cleandata[which(cleandata[,'MARKER']== Mrk),]
          Ptntdata <- Mrkdata[which(Mrkdata[,'CPAN']==Pnt), ]
          output[{i-1}*nPatients+j,1] <- Mrk
          output[{i-1}*nPatients+j,2] <- Pnt
          for (k in 1:6){
            output[{i-1}*nPatients+j,k+2] <- summary(Ptntdata[,'RESULT'])[k]
            #histogram(~Mrkdata [,'RESULT'])
          }
          #output[j,9]<- quantile(Mrkdata[,'RESULT'],c(.25,.75))[1]
          #output[j,10]<- quantile(Mrkdata[,'RESULT'],c(.25,.75))[2]
        }        
      } 
    })
    output$tableoutput <- renderDataTable({df2()}) 
       } )