如何处理 R shiny 中的此错误

Question

When I run this code:

ui1 <- fluidPage(
  textInput("usubjid","Search usubjid",""),
  tableOutput("table")
)

server1 <- function(input,output)
  {
    
    adae0<-reactive({
      if(length(input$usubjid)==0)
      {
        adae
      }
      else
      {
        subset(adae,USUBJID==input$usubjid)
      }
    })    
  
    output$table <- renderTable
    (
      {
        adae0() %>%
          select(USUBJID,AEREFID,AGE,SEX,AEBODSYS)
      }
    )
  }

shinyApp(ui=ui1,server=server1)

The error comes:

I want to know why and how i can fix it. Thanks. I am new to R shiny, and ask for help. Can anybody help me? Thanks a lot!

Answer 1

You are using dplyr without loading the library: After loading dplyr package the code should run. See in server part: library(dplyr)

ui1 <- fluidPage(
  textInput("usubjid","Search usubjid",""),
  tableOutput("table")
)

server1 <- function(input,output)
library(dplyr)
  {
  
  adae0<-reactive({
    if(length(input$usubjid)==0)
    {
      adae
    }
    else
    {
      subset(adae,USUBJID==input$usubjid)
    }
  })    
  
  output$table <- renderTable
  (
    {
      adae0() %>%
        select(USUBJID,AEREFID,AGE,SEX,AEBODSYS)
    }
  )
}

shinyApp(ui=ui1,server=server1)