r - R Shiny“错误：要写入的文本必须是长度为一的字符向量”

Question

我正在尝试帮助朋友调试他们对基本闪亮应用程序的第一次尝试。我知道有些事情对这段代码并不理想（至少拼写），但我不明白为什么它应该抛出主题错误......

ui.R 是

library(magrittr)
library(dplyr)
library(tidyr)

olympic <- read.csv("olympic_games.csv", header = TRUE)


shinyServer(fluidPage(
  titlePanel("Olympic games medals from 2002 - 2012"),

  country <- levels(olympic$Country),

  total_medal <- unique(olympic$Total.Medal),

  sidebarLayout(
    sidebarPanel(
      helpText("Choose the contry to know how many medals they have"),

      selectInput("Country",
                  label = "chose country",
                  choices = country,
                  selected = country[1]),

      selectInput("country1",
                  label = "chose country",
                  choices = country,
                  selected=country[2]),
      br(),
      radioButtons("color", "Select the colour of histogram if you like?",
                   choices=c("green","red","yellow"), selected= "green")
    ),
    mainPanel(
      plotOutput("Olympic_games")
    )
  ))
)

和 server.r

library(magrittr)
library(dplyr)
library(tidyr)
library(ggplot2)

shinyServer(
  function(input,output,session){
    olympic <- read.csv("olympic_games.csv", header = TRUE)
    output$Olympic_games <- renderPlot({

      olympic1 <- subset(olympic,Country==input$Country)
      olympic2 <- subset(olympic,Country==input$country1)
      col <- input$color
      frames <- rbind(olympic1,olympic2)
      ggplot(frames, aes(Total.Medals))+
        geom_histogram(aes(Total.Medals,fill=Country),color=col) + facet_grid(Country~Total.Medals)
    }
    )
  }  
)

当读取 olympic_games.csv 文件时，数据看起来像

head(olympic)
           Athlete Age       Country Year Closing.Ceremony.Date      Sport Gold.Medals Silver.Medals
1   Michael Phelps  23 United States 2008             8/24/2008   Swimming           8             0
2   Michael Phelps  19 United States 2004             8/29/2004   Swimming           6             0
3   Michael Phelps  27 United States 2012             8/12/2012   Swimming           4             2
4 Natalie Coughlin  25 United States 2008             8/24/2008   Swimming           1             2
5    Aleksey Nemov  24        Russia 2000             10/1/2000 Gymnastics           2             1
6    Alicia Coutts  24     Australia 2012             8/12/2012   Swimming           1             3
  Bronze.Medals Total.Medals
1             0            8
2             2            8
3             0            6
4             3            6
5             3            6
6             1            5

当您尝试将两个字符串传递给一个只需要一个的闪亮的 UI 函数时，我发现了对这个错误的引用，但我在这里看不到任何可能发生这种情况的地方。

标签： rshiny