[英]relevel a reactive variable in shiny
我想使用閃亮來讀取 CSV 文件,然后允許用戶能夠在該文件的特定列中選擇參考級別。 想象一下這樣的數據:
mydata <- data.frame(letter = rep(letters[1:3], 3), num = 1:9)
write.csv(mydata, "mydata.csv", row.names = FALSE)
這是我的代碼:
library(shiny)
ui <- fluidPage(
fileInput(
"file",
label = "File Input",
accept = ".csv"
),
selectInput(
inputId = "ref",
label = "Reference Outcome",
choices = NULL
),
actionButton( inputId = "action",
label = "action"),
textOutput("text")
)
server <- function(input, output, session) {
observe({
updateSelectInput(session,
"ref",
choices = unique(data()[,1]))
})
data <- reactive({
inFile <- req(input$file)
fileinput <- read.csv(inFile$datapath, header = TRUE, stringsAsFactors = FALSE)
return(fileinput)
})
observeEvent(input$action,{
data()$letter <- factor(data()$letter)
data()$letter <- relevel(data()$letter, ref = input$ref)
output$text <- renderText({
paste("Your reference level is: ", levels(data()$letter)[1])
})
})
}
shinyApp(ui, server)
我收到此錯誤:
Warning: Error in <-: invalid (NULL) left side of assignment
[No stack trace available]
我知道您不應該在賦值左側使用反應變量,但是在將數據作為反應變量導入后如何重新調整數據?
嘗試這個
server <- function(input, output, session) {
rv <- reactiveValues(df=NULL)
observe({
updateSelectInput(session,
"ref",
choices = unique(data()[,1]))
})
data <- reactive({
inFile <- req(input$file)
fileinput <- read.csv(inFile$datapath, header = TRUE, stringsAsFactors = FALSE)
return(fileinput)
})
observeEvent(input$action,{
rv$df <- data()
rv$df$letter <- factor(rv$df$letter)
rv$df$letter <- relevel(rv$df$letter, ref = input$ref)
output$text <- renderText({
paste("Your reference level is: ", levels(rv$df$letter)[1])
})
})
}
這是幾乎相同的答案,只是每次單擊操作按鈕時數據框值都不會更新。 它僅在文件上傳時更新。
library(shiny)
mydata <- data.frame(letter = rep(letters[1:3], 3), num = 1:9)
write.csv(mydata, "mydata.csv", row.names = FALSE)
ui <- fluidPage(
fileInput(
"file",
label = "File Input",
accept = ".csv"
),
selectInput(
inputId = "ref",
label = "Reference Outcome",
choices = NULL
),
actionButton( inputId = "action",
label = "action"),
textOutput("text")
)
server <- function(input, output, session) {
observe({
updateSelectInput(session,
"ref",
choices = unique(data()[,1]))
})
data <- reactive({
inFile <- req(input$file)
fileinput <- read.csv(inFile$datapath, header = TRUE, stringsAsFactors = FALSE)
r$df <- fileinput
})
r <- reactiveValues(
df = NULL
)
observeEvent(input$action,{
r$df$letter <- factor(r$df$letter)
r$df$letter <- relevel(r$df$letter, ref = input$ref)
output$text <- renderText({
paste("Your reference level is: ", levels(r$df$letter)[1])
})
})
}
shinyApp(ui, server)
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.