在Shiny中定义变量（动态）

Question

我正在创建一个闪亮的应用程序，允许您为了运行线性回归而上传带有一些数据（相关和独立变量）的Excel文件。

我正在使用read.xlsx加载将在第一个选项卡中输出表格的excel文件。在第二个选项卡中，我想要一个小部件，它允许您选择因变量和另一个要求您选择独立变量的输入小部件。这些变量将是加载的数据列标题的函数。因此，假设加载的数据如下所示：

A  B  C  D  E  F G 
22000 0.605 0.352 1.125 103.5 162 7107.263017 
22000 0.495 0.352 1.375 126.5 162 4569.734496 
22000 0.495 0.352 1.375 103.5 198 4649.524562 
18000 0.495 0.352 1.125 126.5 198 4495.776272 

其中G是自变量。我希望将列标题用作我的第二个选项卡上变量选择的基础。 我面对的是连接加载的Excel文件头（列名）是我的参数选择，因为我在我的UI定义他们为我选择的变量问题：

selectizeInput('inv',"In", choices = var, multiple = TRUE), 
selectizeInput('out',"Out", choices = pred, multiple = FALSE) 

所以VAR和预解码都在服务器上定义并因此产生一个错误：找不到对象'var'。

我该如何解决这个问题。这是迄今为止代码：

ui <- fluidPage(

    titlePanel("Hi"), 
    sidebarLayout(position = "left", 
       sidebarPanel(
        conditionalPanel(condition = "input.tabs1==1", 
            tags$style(type='text/css', ".well { max-width: 20em; }"), 
            # Tags: 
            tags$head(
            tags$style(type="text/css", "select[multiple] { width: 100%; height:10em}"), 
            tags$style(type="text/css", "select { width: 100%}"), 
            tags$style(type="text/css", "input { width: 19em; max-width:100%}") 
            ), 

            # Select filetype: 
            selectInput("readFunction", "Function to read data:", c(
            # Base R: 
            "read.table", 
            "read.csv", 
            "read.csv2", 
            "read.delim", 
            "read.delim2", 
            "readWorksheet", 
            "read_excel", 
            "read.xlsx" 

            )), 

            # Argument selecter: 
            htmlOutput("ArgSelect"), 

            # Argument field: 
            htmlOutput("ArgText"), 

            # Upload data: 
            fileInput("file", "Upload data-file:"), 

            # Variable selection: 
            htmlOutput("varselect"), 

            br(), 

            textInput("name","Dataset name:","Data")), 
        conditionalPanel(condition = "input.tabs1==2", 
            #fileInput('file', 'Choose file to upload.'), 
            selectizeInput('invar',"Select Regression Input Variables", choices = varnames, multiple = TRUE), 
            selectizeInput('outvar',"Select Regression Output Variable", choices = predictors, multiple = FALSE) 

       ), 
       mainPanel(
        tabsetPanel(id="tabs1", 
           tabPanel("Data File",value = 1,tableOutput("table")), 
           tabPanel("LM Plot", value=2, plotOutput("PlotLM"))) 

       ) 
       ) 

)) 




    server<-function(input, output) { 
    options(shiny.maxRequestSize=30*1024^2) 

    ### Argument names: 
    ArgNames <- reactive({ 
    Names <- names(formals(input$readFunction)[-1]) 
    Names <- Names[Names!="..."] 
    return(Names) 
    }) 

    # Argument selector: 
    output$ArgSelect <- renderUI({ 
    if (length(ArgNames())==0) return(NULL) 

    selectInput("arg","Argument:",ArgNames()) 
    }) 

    ## Arg text field: 
    output$ArgText <- renderUI({ 
    fun__arg <- paste0(input$readFunction,"__",input$arg) 

    if (is.null(input$arg)) return(NULL) 

    Defaults <- formals(input$readFunction) 

    if (is.null(input[[fun__arg]])) 
    { 
     textInput(fun__arg, label = "Enter value:", value = deparse(Defaults[[input$arg]])) 
    } else { 
     textInput(fun__arg, label = "Enter value:", value = input[[fun__arg]]) 
    } 
    }) 


    ### Data import: 
    Dataset <- reactive({ 
    if (is.null(input$file)) { 
     # User has not uploaded a file yet 
     return(data.frame()) 
    } 

    args <- grep(paste0("^",input$readFunction,"__"), names(input), value = TRUE) 

    argList <- list() 
    for (i in seq_along(args)) 
    { 
     argList[[i]] <- eval(parse(text=input[[args[i]]])) 
    } 
    names(argList) <- gsub(paste0("^",input$readFunction,"__"),"",args) 

    argList <- argList[names(argList) %in% ArgNames()] 

    Dataset <- as.data.frame(do.call(input$readFunction,c(list(input$file$datapath),argList))) 
    return(Dataset) 
    }) 

    # Select variables: 
    output$varselect <- renderUI({ 

    if (identical(Dataset(), '') || identical(Dataset(),data.frame())) return(NULL) 

    # Variable selection:  
    selectInput("vars", "Variables to use:", 
       names(Dataset()), names(Dataset()), multiple =TRUE)    
    }) 

    # Show table: 
    output$table <- renderTable({ 

    if (is.null(input$vars) || length(input$vars)==0) return(NULL) 

    return(Dataset()[,input$vars,drop=FALSE]) 
    }) 

Answer 1

你可以尝试使用uiOutput和renderUI做到这一点。

服务器

：

varnames <- reactive({ 
    colnames(Dataset()) 
}) 

output$selectize1 <- renderUI({ 
    selectizeInput('invar',"Select Regression Input Variables", choices = varnames(), multiple = TRUE) 

}) 

在UI：

uiOutput('selectize1')