运行用于创建预测模型和相应图的闪亮应用时出错

Question

我是 shiny 的新手，刚刚使用 R 中可用的 ToothGrowth 数据构建了这个 shiny 应用程序。数据摘要如下：

 str(ToothGrowth)
'data.frame':   60 obs. of  3 variables:
 $ len : num  4.2 11.5 7.3 5.8 6.4 10 11.2 11.2 5.2 7 ...
 $ supp: Factor w/ 2 levels "OJ","VC": 2 2 2 2 2 2 2 2 2 2 ...
 $ dose: num  0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 ...

我的ui.R文件如下：

library(shiny)

# Define UI for application 
shinyUI(fluidPage(
    
    # Application title
    titlePanel("Tooth length prediction"),
    
    # Sidebar with options selectors
    sidebarLayout(
        sidebarPanel(
            h3(helpText("Select:")),
            selectInput("dos", label = h4("Dose Value"), choices = list("0.5", "1" ,"2")),
            selectInput("sup", label = h4("Supplement Type"),
                        choices = list("OJ" = "OJ", "VC" = "VC"))
 
        ),
        
        # Show a plot and regression line
        mainPanel(
            plotOutput("distPlot"),
            h4("Predicted tooth value is:"),
            h3(textOutput("result"))
        )
    )
))

我的server.R文件如下：

library(shiny)
library(ggplot2)
library(dplyr)

head(ToothGrowth)

shinyServer(function(input, output) {
    output$distPlot <- renderPlot({
        # build linear regression model
        ToothGrowth$dose <- as.numeric(ToothGrowth$dose)
        fit <- lm( len~dose + supp , ToothGrowth)
        # predicts the length
        pred <- predict(fit, newdata = data.frame(dose = input$dos,
                                                  supp = input$sup
                                                 ))
        # Draw the plot using ggplot2
        plot <- ggplot(data=ToothGrowth, aes(x=dose, y = len))+
            geom_point(aes(color = supp), alpha = 0.3)+
            geom_smooth(method = "lm")
          
        plot
    })
    output$result <- renderText({
        # Renders the text for the prediction below the graph
        fit <- lm( len~dose + supp , ToothGrowth)
        pred <- predict(fit, newdata = data.frame(dose = input$dos,
                                                  supp = input$sup
        ))
       
    })
    
})

当我运行应用程序时，出现此错误： Error in : variable 'dose' was fitted with type "numeric" but type "character" was supplied

我没有看到 ggplot 创建的任何渲染图，也没有看到线性模型的预测输出结果，如下所示：

如果有人能告诉我我做错了什么，我将不胜感激。

非常感谢！

此致

Answer 1

在服务器部分添加as.numeric()到dose：将 input$dos 替换为 as.numeric(input$dos)

library(shiny)
library(ggplot2)
library(dplyr)

head(ToothGrowth)

shinyServer(function(input, output) {
  output$distPlot <- renderPlot({
    # build linear regression model
    ToothGrowth$dose <- as.numeric(ToothGrowth$dose)
    fit <- lm( len~dose + supp , ToothGrowth)
    # predicts the length
    pred <- predict(fit, newdata = data.frame(dose = as.numeric(input$dos),
                                              supp = input$sup
    ))
    # Draw the plot using ggplot2
    plot <- ggplot(data=ToothGrowth, aes(x=dose, y = len))+
      geom_point(aes(color = supp), alpha = 0.3)+
      geom_smooth(method = "lm")
    
    plot
  })
  output$result <- renderText({
    # Renders the text for the prediction below the graph
    fit <- lm( len~dose + supp , ToothGrowth)
    pred <- predict(fit, newdata = data.frame(dose = as.numeric(input$dos),
                                              supp = input$sup
    ))
    
  })
  
})

运行用于创建预测模型和相应图的闪亮应用时出错

Error while running a shiny app to create a predictive model and a corresponding plot

r

linear-regression

ggplot2

shiny

运行 用于创建预测模型和相应图的闪亮应用时出错

Error while running a shiny app to create a predictive model and a corresponding plot

r

linear-regression

ggplot2

shiny

运行用于创建预测模型和相应图的闪亮应用时出错