r閃亮 - 通過選擇值減少上傳的數據集

Question

我正在嘗試編寫一個腳本來上傳.csv文件並在UI中引發子選項（以複選框的形式）。上傳後，顯示以前不可見的複選框，顯示實際的數據值。同時，還會出現一個動作按鈕，在選定的數據值（通過複選框）（可能）改變之後被點擊。

那麼我有什麼？
1）上傳 - 確定。
2）選擇並顯示覆選框 - 確定。
3）顯示操作按鈕 - 確定。
4）正確執行所需的操作（=數據子集） - 不正確;子集顯然會返回空或NULL數據幀。

任何幫助將不勝感激。

這是代碼。

我會補充說，我基於子集的Dte字段是一個日期字段，它最初在csv中爲dd/mm/yyyy格式且不含引號。

library(shiny) 
library(lubridate) 

ui = fluidPage(sidebarPanel(width = 2, 
          fileInput('files', '', accept = c('text/csv','text/comma-separated-values','text/tab-separated-values','text/plain','.csv','.tsv')), 
          checkboxInput('header', 'Header', TRUE), 
          radioButtons('sep', 'Separator', c(Comma=',',Semicolon=';',Tab='\t'), selected=';'), 
          radioButtons('quote', 'Quote', c(None='','Double Quote'='"','Single Quote'="'"), selected='"'), 
          uiOutput('apply')), 
       mainPanel(width = 10, uiOutput('years'), dataTableOutput("tabel4") 
       ) 
) 

server = function(input, output, session) { 
    ### if a csv is selected (through fileInput()), it is read 
    vis0 <- eventReactive(input$files, { 
    vis <- read.csv(input$files$datapath, header = input$header, sep = input$sep, quote = input$quote, 
          stringsAsFactors =FALSE) 
    vis$Dte <- as.Date(as.character(vis$Dte), "%d/%m/%Y") 
    vis$year <- factor(year(vis$Dte)) 
    vis 
    }) 
    ### button appearing only after 
    output$apply <- renderUI({ 
    if (is.null(input$files)) return() 
    actionButton("Load", "APPLY DATA") 
    }) 
    ### get checkbox values from data and throw them back to UI 
    output$years <- renderUI({ 
    df <- vis0() 
    df$year <- as.character(df$year) 
    if (is.null(df)) return(NULL) 
    items= sort(unique(df$year)) 
    names(items)=items 
    checkboxGroupInput("dependent","Check or uncheck years to be included or excluded", 
         choices=items, selected = items, inline = TRUE) 
    }) 
    ### use selected checkbox values to reduce initial dataset 
    vis1 <- reactive({ 
    if (is.null(input$Load)) return() 
    if (input$Load==0) return() 
    data <- vis0() 
    data <- subset(data, as.character(year) %in% input$years) 
    data 
    }) 
    ### using the checkbox-reduced data to create a table 
    output$tabel4 <- renderDataTable({ 
    vis1() 
    }) 
    } 

shinyApp(ui = ui, server = server, options = list(launch.browser=TRUE)) 

Answer 1

我找到了解決方案！

一個愚蠢的錯誤（至少）是dependent必須是years。也許有更多（特別是在if檢查），我修正了，但沒有正確跟蹤，但下面的代碼工作。

library(shiny) 
library(lubridate) 

ui = fluidPage(sidebarPanel(width = 2, 
          fileInput('files', '', accept = c('text/csv','text/comma-separated-values','text/tab-separated-values','text/plain','.csv','.tsv')), 
          checkboxInput('header', 'Header', TRUE), 
          radioButtons('sep', 'Separator', c(Comma=',',Semicolon=';',Tab='\t'), selected=';'), 
          radioButtons('quote', 'Quote', c(None='','Double Quote'='"','Single Quote'="'"), selected='"'), 
          uiOutput('apply')), 
       mainPanel(width = 10, uiOutput('years'),tags$br(),tags$br(), 
         textOutput('showyrs'),tags$br(),tags$br(), 
         textOutput('yrz'),tags$br(),tags$br(), 
         dataTableOutput("tabel4") 
       ) 
) 


###################################################################### 

server = function(input, output, session) { 
    ### if a csv is selected (through fileInput()), it is read 
    vis0 <- reactive({ 
    req(input$files) 
    vis <- read.csv(input$files$datapath, header = input$header, sep = input$sep, quote = input$quote, 
          stringsAsFactors =FALSE) 
    vis$Dte <- as.Date(as.character(vis$Dte), "%d/%m/%Y") 
    vis$year <- factor(year(vis$Dte)) 
    vis 
    }) 

    ### button appearing only after 
    output$apply <- renderUI({ 
    if (is.null(input$files)) return() 
    actionButton("Load", "APPLY DATA") 
    }) 

    ### get checkbox values from data and throw them back to UI 
    output$years <- renderUI({ 
    req(vis0) 
    df <- vis0() 
    df$year <- as.character(df$year) 
    if (is.null(df)) return(NULL) 
    items= sort(unique(df$year)) 
    names(items)=items 
    checkboxGroupInput("years","Check or uncheck years to be included or excluded", 
         choices=items, selected = items, inline = TRUE) 
    }) 

    ### show input$years 
    output$showyrs <- renderText({ 
    req(input$files) 
    if (is.null(input$years)) { 
     "Nothing..." 
    } else if (input$years==0) { 
     "Nothing..." 
    } else {input$years} 
    }) 

    ### use selected checkbox values to reduce initial dataset 
    vis1 <- reactive({ 
    req(input$years) 
    if (is.null(input$Load)) return() 
    if (input$Load==0) return() 
    data <- vis0() 
    data <- subset(data, as.character(year) %in% input$years) 
    data 
    }) 

    ### using the checkbox-reduced data to create a table 
    output$tabel4 <- renderDataTable({ 
    vis1() 
    }) 
    } 

shinyApp(ui = ui, server = server, options = list(launch.browser=TRUE))