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[英]Error in [.data.frame: undefined columns selected for worldcloud in Shiny
[英]R Shiny Error in [.data.frame: undefined columns selected
我正在嘗試在 Shiny 中構建簡單的 csv 上傳示例。 上傳 csv 文件,將 header 存儲在 Select 輸入控制並顯示表 Z78E6221F6393D1356DZ681 中的每一列。 一旦我上傳任何 csv 文件,它就會顯示以下錯誤
[.data.frame 中的錯誤:選擇了未定義的列
但是,如果再次上傳相同的 csv 文件,則不會顯示錯誤。
library(shiny)
library(shinyjs)
ui <- pageWithSidebar(
headerPanel("CSV Upload test"),
sidebarPanel(
fileInput("datafile", h5("Choose CSV file:"),
accept=c('text/csv', 'text/comma-separated-values,text/plain')),
htmlOutput("varselect", inline=TRUE),
selectInput("vars", label = h5("Select a variable:"), choice=NULL, selected = NULL,
multiple=FALSE, selectize=TRUE),
actionButton("unselect", label="Clear All"),
br()
),
mainPanel(dataTableOutput("table")))
server <- function(session,input, output) {
Dataset <- reactive({
infile <- input$datafile
if (is.null(infile)) {
return(NULL)
}
read.csv(infile$datapath)
})
observe({
if (identical(Dataset(), '') || identical(Dataset(),data.frame()))
return(NULL)
updateSelectInput(session, inputId="vars",
choices=names(Dataset()), selected=NULL)
})
observe({
if (input$unselect > 0) {
if (identical(Dataset(), '') || identical(Dataset(),data.frame()))
return(NULL)
updateSelectInput(session, inputId="vars",
choices=names(Dataset()), selected=NULL)
}
})
output$table <- renderDataTable({
if (is.null(input$vars) || length(input$vars)==0) return(NULL)
validate(need(Dataset(), "Awaiting data"))
return(Dataset()[,input$vars,drop=FALSE])
})
}
shinyApp(ui, server)
同樣在 selectInput function if I change option for multiple = TRUE 中,csv 上傳開頭的此錯誤不會顯示。
selectInput("vars", label = h5("Select a variable:"), choice=NULL, selected = NULL,
multiple=FALSE, selectize=TRUE)
感謝有人可以幫助我了解這里發生了什么。 有什么解決辦法嗎?
以下消除了您的錯誤:
output$table <- renderDataTable({
validate(need(Dataset(), "Awaiting data"))
if (is.null(Dataset()) || is.null(input$vars) || length(input$vars)==0) {
return(NULL)
} else{
selected_vars <- names(Dataset()) %in% input$vars
Dataset()[,selected_vars,drop=FALSE]
}
})
除了@YBS的anwser,用req
更干凈一點
library(shiny)
library(shinyjs)
ui <- pageWithSidebar(
headerPanel("CSV Upload test"),
sidebarPanel(
fileInput("datafile", h5("Choose CSV file:"),
accept=c('text/csv', 'text/comma-separated-values,text/plain')),
htmlOutput("varselect", inline=TRUE),
selectInput("vars", label = h5("Select a variable:"), choice=NULL, selected = NULL,
multiple=FALSE, selectize=TRUE),
actionButton("unselect", label="Clear All"),
br()
),
mainPanel(dataTableOutput("table")))
server <- function(session,input, output) {
Dataset <- reactive({
req(input$datafile)
infile <- input$datafile
try( {
read.csv(infile$datapath)
})
})
observeEvent(Dataset(), {
updateSelectInput(session, inputId="vars",
choices=names(Dataset()), selected=NULL)
})
observeEvent(input$unselect, {
req(Dataset())
updateSelectInput(session, inputId="vars",
choices=names(Dataset()), selected=NULL)
})
output$table <- renderDataTable({
validate( need(Dataset(), "Awaiting data")
, need(input$vars, "Select variable")
)
return(Dataset()[,input$vars,drop=FALSE])
})
}
shinyApp(ui, server)
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