根據名稱過濾CSV檔案并在RShiny上更新selectizeInput

我是 RShiny 的新手（和一般的 R），不太清楚如何做以下事情。我有一個包含 50 個以 P2.csv、P3.csv 或 P5.csv 結尾的 CSV 檔案的串列。我想制作一個允許用戶選擇特定價格（P2、P3、P5）的應用程式，然后向他們展示具有該結束模式的 csv 檔案串列，然后用戶可以從中選擇最多 3 個需要加載到記憶體中。

我已經分別找到了如何列出具有特定結尾的所有檔案，并且我認為我需要使用 updateSelectizeInput 以便每次用戶選擇價格（例如 P2）時，他都會看到所有 csv 檔案 appleP2.csv、orangeP2 .csv 等例如，但想不出辦法使這項作業。

任何幫助是極大的贊賞！謝謝你。

library(shiny)

#listing the csv files ending with a same pattern 
same_price_P2<-list.files(pattern="P2.csv")
same_price_P3<-list.files(pattern="P3.csv")
same_price_P5<-list.files(pattern="P5.csv")

shinyUI(fluidPage(
  
  titlePanel("Price of fruit"),
  
  #user can select the price of the fruit
  selectInput("Price", "Price", choices = c("5 euros"="P5", "2 euros"="P2", "3 euros"="P3"), selected="P2", multiple=FALSE)),
  
  #user must be presented only with the CSV files associated to the selected price and can select maximum of 3 
  #files to be read 
  selectizeInput("Fruit", "Fruit", choices = "", selected = NULL, multiple=TRUE, options=list(maxItems=3)),
  

  
  tableOutput("dataset")
)


shinyServer(function(session, input, output){
  
  
  #Populate this by filtering through and showing the csv files based on whether they end in P2.csv, P5.csv, P3.csv
  #the selected files by the user should then be read
  observeEvent(
    input$Price,
    updateSelectizeInput(session, "Fruit", "Fruit", 
                      choices = ................[..........==input$Price]))
  
 
  output$dataset <- renderTable({
    data
  })
  
})

uj5u.com熱心網友回復：

您已經找到了主要步驟。

最后的步驟是：

1. choice在函式的引數中插入所有可能的 csv 名稱（無論結尾如何）selectizeInput。（我們在第二步也需要這個向量，因此它是在selectizeInput函式之外指定的。-> all_price）
2. 過濾 中choices的input$Price變數updateSelectizeInput。
3. 將表加載到記憶體中。

下面的代碼將幫助您完成第一步。因為這似乎是您目前正在處理的問題。

library(shiny)

#listing the csv files ending with a same pattern 
same_price_P2 <- c("appleP2.csv",  "bananaP2.csv", "cranberryP2.csv", "dateP2.csv")
same_price_P3 <- c("appleP3.csv",  "bananaP3.csv", "cranberryP3.csv", "dateP3.csv")
same_price_P5 <- c("appleP5.csv",  "bananaP5.csv", "cranberryP5.csv", "dateP5.csv")
all_price <- c(same_price_P2, same_price_P3, same_price_P5)

ui <- fluidPage(
  
  titlePanel("Price of fruit"),
  
  #user can select the price of the fruit
  selectInput("Price",
              "Price",
              choices = c("5 euros" = "P5", 
                          "2 euros" = "P2",
                          "3 euros" = "P3"),
              selected = "P2",
              multiple = FALSE),
  
  #user must be presented only with the CSV files associated to the selected price and can select maximum of 3 
  #files to be read 
  selectizeInput("Fruit",
                 "Fruit", 
                 choices = all_price, 
                 selected = NULL, 
                 multiple =  TRUE,
                 options = list(maxItems = 3)),
  
  
  textOutput("dataset")
)


server <- function(input, output, session){
  
  
  #Populate this by filtering through and showing the csv files based on whether they end in P2.csv, P5.csv, P3.csv
  #the selected files by the user should then be read
  observe({
    updateSelectizeInput(session, 
                         "Fruit", 
                         "Fruit", 
                         choices = grep(paste0(input$Price,
                                               ".csv$"),
                                        all_price,
                                        value = T))
    })
  
  
  output$dataset <- renderText({
    input$Fruit
  })
  
}

shinyApp(ui, server)

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