如何在闪亮的多个输出中检索循环生成的变量

Question

使用 iris 数据，我运行在 r shiny 反应式表达式中循环生成下面的变量 species_table 我想访问的内容在随后的输出函数中。我在 this link 中关注了 guidance 但是当稍后调用 species_function 函数时，我收到一条错误消息说 species_table 找不到。如何检索输出函数中的 species_table 内容以显示在 ui?

library(shiny)
data(iris)

ui <- fluidPage(
  
  mainPanel(
    fluidRow(selectInput("portfolio", label = "Select Species", choices = unique(iris$Species))),
    fluidRow(tableOutput("result")))

)

server <- function(input, output) {
  
  species_list <- reactiveValues(a = "setosa", b = "versicolor", c = "virginica")  
  
  species_function <- reactive({  
    species_table <- list()
    for (i in reactiveValuesToList(species_list)){
      local({
        j <- i
        species_table[[reactive({j})()]] <<- iris[iris$Species==reactive({j})(),]  
      })
    }
    
    print(species_table[[input$portfolio]])
    
    return(list(species_table[["setosa"]], species_table[["versicolor"]], species_table[["viginica"]]))
    
  })
  
  output$result <- renderTable({
    
    species_table2 <- list()
    
    for (p in reactiveValuesToList(species_list)){
      local({
        q <- p
        species_table2[[reactive({q})()]] <<- species_function()[[species_table]][[reactive({q})()]][1:5, c("Sepal.Length", "Sepal.Width")]       
      })
    }
    
    print(species_table2[[input$portfolio]])
    return(species_table2[[input$portfolio]])
    
  })
  
}

shinyApp(ui = ui, server = server)

Answer 1

您的 species_table 在其定义的反应式之外不可用。相反，return 一个命名列表，你会得到你想要的输出。试试这个

library(shiny)
data(iris)

ui <- fluidPage(
  
  mainPanel(
    fluidRow(selectInput("portfolio", label = "Select Species", choices = unique(iris$Species))),
    fluidRow(tableOutput("result"))
    )
    
)

server <- function(input, output) {
  
  species_list <- reactiveValues(a = "setosa", b = "versicolor", c = "virginica") 
  
  species_function <- reactive({
    
    species_table <- list()
    for (i in reactiveValuesToList(species_list)){
      local({
        j <- i
        species_table[[j]] <<- iris[iris$Species==j,]
      })
    }

    #print(rv$species_table[[input$portfolio]])

    return(list("setosa" = species_table[["setosa"]],"versicolor" = species_table[["versicolor"]],"virginica" = species_table[["virginica"]]))
    
  })
  
  output$result <- renderTable({
    input$portfolio
    species_table2 <- list()

    for (p in reactiveValuesToList(species_list)){
      local({
        q <- p
        species_table2[[reactive({q})()]] <<- species_function()[[reactive({q})()]][1:5, c("Sepal.Length", "Sepal.Width")]
      })
    }

    print(species_table2[[input$portfolio]])
    return(species_table2[[input$portfolio]])

  })
  
}

shinyApp(ui = ui, server = server)

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