Question

我正在尝试为项目构建一个闪亮的应用程序，我想我已经完成了，一切似乎都正常工作但我在运行应用程序时在控制台中不断收到此错误：

Error in grep(input$predict, columns) : invalid 'pattern' argument
Error in parse(text = x) : <text>:2:0: unexpected end of input
1: Ozone  ~  
   ^
Error in parse(text = x) : <text>:2:0: unexpected end of input
1: Ozone  ~  
   ^

这是我的ui.R代码：

library(shiny)

# Define UI for airquality data application
shinyUI(pageWithSidebar(

    # Application title
    headerPanel("Air Quality Relationships & Predictions"),

    sidebarPanel(
            selectInput("outcome", "Outcome:", list("O Zone" = "Ozone", 
                                                    "Solar Radiation" = "Solar.R",
                                                    "Wind" = "Wind",
                                                    "Temperature" = "Temp")),
            uiOutput("predictor"),
            uiOutput("slider"),
            h5(textOutput("guess"))
    ),

    mainPanel(
            plotOutput("ioPlot")
    )
))

这是server.R的代码：

    library(shiny)
    library(datasets)

    #import dataset
    airData <- airquality

    #make list of columns for dropdowns
    columns <- list("O Zone" = "Ozone", "Solar Radiation" = "Solar.R", "Wind" = "Wind", "Temperature" = "Temp")

    # Define server logic
    shinyServer(function(input, output, session) {

            #set dropdown so it only shows 3 remaining columns, won't compare a variable to itself
            output$predictor = renderUI({
                    outc <- input$outcome
                    selectInput("predict", "Predictor:", columns[-grep(outc,columns)])
            })

            #setup the slider for the current selections, default to mean, set max and min to the observed max and min
            output$slider = renderUI({
                    slLabel = paste("Adjust to predict ", names(columns[grep(input$outcome,columns)]), "using this value for ", names(columns[grep(input$predict,columns)]), ":")
                    slVal = round(mean(airData[,input$predict], na.rm=TRUE),0)
                    slMin = round(min(airData[,input$predict], na.rm=TRUE),0)
                    slMax = round(max(airData[,input$predict], na.rm=TRUE),0)
                    sliderInput('slide', slLabel, value = slVal, min = slMin, max = slMax, step=1,)
            })

            #create formula for plot
            formulaText <- reactive({
                    paste(input$outcome, " ~ ", input$predict)
            })

            #create text for prediction
            output$guess <- renderText({
                    fit <- lm(as.formula(formulaText()), data=airData)
                    slp <- fit$coeff[2]
                    yint <- fit$coeff[1]
                    predout <- round(yint + slp * input$slide,2)
                    paste("Predicted outcome for ", names(columns[grep(input$outcome,columns)]), ": ", predout)
            })

            #create plot and fitted line
            output$ioPlot <- renderPlot({
                    fit <- lm(as.formula(formulaText()), data=airData)
                    plot(as.formula(formulaText()), 
                            data = airData, xlab=names(columns[grep(input$predict,columns)]), ylab=names(columns[grep(input$outcome,columns)]))
                    abline(fit, col="red")
                    title(main= paste(names(columns[grep(input$outcome,columns)]), " vs. ", names(columns[grep(input$predict,columns)])))
            })
    })

Answer 1

我认为问题是由于您将columns分组为predict selectInput

的方式

试试这个

output$predictor = renderUI({
            selectInput("predict", "Predictor:", columns[columns!=input$outcome])
})

除了为columns选择的内容外，list input$outcome应该为您提供所有内容。

修改我刚刚注意到你也多次使用grep来为输出粘贴一些文本。相反，你应该使用如下语句：

xlab=names(columns[columns==input$predict])

也就是说，您不需要grep，您可以直接将columns分组。

控制台中的闪亮应用程序错误

1 个答案: