你好闪亮的应用程序在反应性表达中给了我错误

Posted 2023-02-25

【中文标题】你好闪亮的应用程序在反应性表达中给了我错误

【英文标题】：Hello shiny app gives me error in reactive expression

【发布时间】：2021-03-20 09:07:31

【问题描述】：

您好，我正在尝试在此链接中重现 RStudio 闪亮应用程序的示例： https://shiny.rstudio.com/articles/tabsets.html shinyapp 给出了 d() 反应表达式的错误，我尝试更改表达式但给了我错误： 代码是：

图书馆（闪亮）

为随机分发应用定义 UI ----

ui

# App title ----
titlePanel("Tabsets"),

# Sidebar layout with input and output definitions ----
sidebarLayout(
    
    # Sidebar panel for inputs ----
    sidebarPanel(
        
        # Input: Select the random distribution type ----
        radioButtons("dist", "Distribution type:",
                     c("Normal" = "norm",
                       "Uniform" = "unif",
                       "Log-normal" = "lnorm",
                       "Exponential" = "exp")),
        
        # br() element to introduce extra vertical spacing ----
        br(),
        
        # Input: Slider for the number of observations to generate ----
        sliderInput("n",
                    "Number of observations:",
                    value = 500,
                    min = 1,
                    max = 1000)
        
    ),
    
    # Main panel for displaying outputs ----
    mainPanel(
        
        # Output: Tabset w/ plot, summary, and table ----
        tabsetPanel(type = "tabs",
                    tabPanel("Plot", plotOutput("plot")),
                    tabPanel("Summary", verbatimTextOutput("summary")),
                    tabPanel("Table", tableOutput("table"))
        )
        
    )
)

)

为随机分发应用定义服务器逻辑----

服务器

# Reactive expression to generate the requested distribution ----
# This is called whenever the inputs change. The output functions
# defined below then use the value computed from this expression
d <- reactive(
    dist <- switch(input$dist,
                   norm = rnorm,
                   unif = runif,
                   lnorm = rlnorm,
                   exp = rexp,
                   rnorm)
    
    dist(input$n)
)

# Generate a plot of the data ----
# Also uses the inputs to build the plot label. Note that the
# dependencies on the inputs and the data reactive expression are
# both tracked, and all expressions are called in the sequence
# implied by the dependency graph.
output$plot <- renderPlot(
    dist <- input$dist
    n <- input$n
    
    hist(d(),
         main = paste("r", dist, "(", n, ")", sep = ""),
         col = "#75AADB", border = "white")
)

# Generate a summary of the data ----
output$summary <- renderPrint(
    summary(d())
)

# Generate an HTML table view of the data ----
output$table <- renderTable(
    d()
)

创建闪亮的应用程序----

shinyApp（用户界面，服务器）

我运行应用程序时的错误是： 警告：dist 中的错误：无效参数 反应式：d [C:\Users\pruebas\Documents\Shiny_examples\tabs/app.R#63]

有人可以帮助我在 RStudio 的文章中尝试学习我的第一个应用程序，但是这个是错误的，它应该用来教像我这样的人。我也很喜欢 github 但我找到了相同的代码。谢谢。

【问题讨论】：

您的代码运行良好。请重启 RStudio 后再试。

谢谢 YBS 和 Ash。我已经重新启动了 RStudio，应用程序运行良好。！！

【参考方案1】：

您的应用运行良好。

您是将其保存为两个单独的文件，即ui.r 和server.r，还是一个文件，即app.r？

您的代码已设置为将其保存为两个单独的文件，但错误看起来像是您可能已将其保存为单个文件。

尝试将其保存为两个文件：

ui.r

ui <- fluidPage(
    
    # App title ----
    titlePanel("Tabsets"),
    
    # Sidebar layout with input and output definitions ----
    sidebarLayout(
        
        # Sidebar panel for inputs ----
        sidebarPanel(
            
            # Input: Select the random distribution type ----
            radioButtons("dist", "Distribution type:",
                         c("Normal" = "norm",
                           "Uniform" = "unif",
                           "Log-normal" = "lnorm",
                           "Exponential" = "exp")),
            
            # br() element to introduce extra vertical spacing ----
            br(),
            
            # Input: Slider for the number of observations to generate ----
            sliderInput("n",
                        "Number of observations:",
                        value = 500,
                        min = 1,
                        max = 1000)
            
        ),
        
        # Main panel for displaying outputs ----
        mainPanel(
            
            # Output: Tabset w/ plot, summary, and table ----
            tabsetPanel(type = "tabs",
                        tabPanel("Plot", plotOutput("plot")),
                        tabPanel("Summary", verbatimTextOutput("summary")),
                        tabPanel("Table", tableOutput("table"))
            )
            
        )
    )
    
)

server.r

server <- function(input, output) 
    
    # Reactive expression to generate the requested distribution ----
    # This is called whenever the inputs change. The output functions
    # defined below then use the value computed from this expression
    d <- reactive(
        dist <- switch(input$dist,
                       norm = rnorm,
                       unif = runif,
                       lnorm = rlnorm,
                       exp = rexp,
                       rnorm)
        
        dist(input$n)
    )
    
    # Generate a plot of the data ----
    # Also uses the inputs to build the plot label. Note that the
    # dependencies on the inputs and the data reactive expression are
    # both tracked, and all expressions are called in the sequence
    # implied by the dependency graph.
    output$plot <- renderPlot(
        dist <- input$dist
        n <- input$n
        
        hist(d(),
             main = paste("r", dist, "(", n, ")", sep = ""),
             col = "#75AADB", border = "white")
    )
    
    # Generate a summary of the data ----
    output$summary <- renderPrint(
        summary(d())
    )
    
    # Generate an HTML table view of the data ----
    output$table <- renderTable(
        d()
    )
    

【讨论】：

谢谢阿什。我试图将它保存在 2 个文件中，不仅一个但给了我错误：