r-使用removeUI时清除数据

Question

我使用observeEvent插入一个带有insertUI的UI(在下面的示例中，它添加了一个额外的数字输入框(，并使用observe Event通过removeUI删除这些UI。问题是通过这些UI创建的数据没有清除或重置。在下面的示例中，您可以在单独的数字输入框中输入数字，然后按Go!将它们相加。删除元素后，它应该清除我们的数据并重新求和，但它会保留最后添加的数字。

例如，如果第一个框中有1，并且又添加了两个输入框，都有1，则按Go!将它们正确地相加为3。但是，删除两个文本框并按Go!将保持3，而此时它应该只显示1。

我确信我错过了一些简单的东西。我的代表如下：

library(shiny)
ui <- fluidPage(
# Application title
titlePanel("example"),
# button input
sidebarLayout(
sidebarPanel(
numericInput(
"number",
"A Number 1-10",
1,
min = 1,
max = 10,
step = NA,
width = NULL),
#add/remove buttons
fluidRow(column(
6,
actionButton('insertBtn', 'Add Number'), 
actionButton('removeBtn', 'Remove Number'), 
tags$div(id = 'placeholder') 
)),
# go button
fluidRow(column(
6, actionButton(inputId = "go", label = "Go!"),
))
),
# output
mainPanel(
htmlOutput("total")
)
)
)
server <- function(input, output) {

# add text boxes when clicked

inserted <- c()

observeEvent(input$insertBtn, {
btn <- input$insertBtn
id <- paste0('number', btn)
insertUI(
selector = '#placeholder',
## wrap element in a div with id for ease of removal
ui = tags$div(
fluidRow(
numericInput(
id,
"A Number 1-10",
1,
min = 1,
max = 10,
step = NA,
width = NULL)
),
id = id)
)
inserted <<- c(id, inserted)
})
# remove text boxes
observeEvent(input$removeBtn, {
removeUI(
## pass in appropriate div id
selector = paste0('#', inserted[length(inserted)])
)
inserted <<- inserted[-length(inserted)]
})
# add numbers in boxes
final_number_text <- eventReactive(input$go, {


btn <- input$insertBtn
if(btn > 0){

total <- input$number

for(i in 1:btn){

total<- total+ (input[[paste0("number", i)]])
}


} else {

total <- input$number

}

HTML(paste(total))
})
output$total <- renderText({
final_number_text()
})
}
# Run the application 
shinyApp(ui = ui, server = server)

Answer 1

当长度为0 时，我们可能需要无错误的seq_along

for(i in seq_along(inserted)) {...}

Answer 2

请注意，删除数字时，不会减少input$insertBtn的值。因此，您希望只计算inserted中的元素。因此，更换

for(i in 1:btn){...}

带有

lapply(inserted, function(par) {total <<- total + input[[par]]})

全代码

library(shiny)
ui <- fluidPage(
# Application title
titlePanel("example"),
# button input
sidebarLayout(
sidebarPanel(
numericInput(
"number",
"A Number 1-10",
1,
min = 1,
max = 10,
step = NA,
width = NULL),
#add/remove buttons
fluidRow(column(
6,
actionButton('insertBtn', 'Add Number'),
actionButton('removeBtn', 'Remove Number'),
tags$div(id = 'placeholder')
)),
# go button
fluidRow(column(
6, actionButton(inputId = "go", label = "Go!"),
))
),
# output
mainPanel(
htmlOutput("total")
)
)
)
server <- function(input, output, session) {
# add text boxes when clicked
inserted <- c()
observeEvent(input$insertBtn, {
btn <- input$insertBtn
id <- paste0('number', btn)
insertUI(
selector = '#placeholder',
## wrap element in a div with id for ease of removal
ui = tags$div(
fluidRow(
numericInput(
id,
"A Number 1-10",
1,
min = 1,
max = 10,
step = NA,
width = NULL)
),
id = id)
)
# inserted <<- c(id, inserted) ##  removes first one first
inserted <<- c(inserted, id)   ##  removes last one first
})
# remove text boxes
observeEvent(input$removeBtn, {
removeUI(
## pass in appropriate div id
selector = paste0('#', inserted[length(inserted)])
)

inserted <<- inserted[-length(inserted)]
})
# add numbers in boxes
final_number_text <- eventReactive(input$go, {
total <- input$number
if(length(inserted) > 0){
lapply(inserted, function(par) {total <<- total + input[[par]]})
}
HTML(paste(total))
})
output$total <- renderText({
final_number_text()
})
}
# Run the application
shinyApp(ui = ui, server = server)