使用文本输入计算闪亮应用程序中另一个文本输入的值

Question

我想提供输入百分比或数值的选项。当用户输入两者之一时，我希望另一个自动填充。

所以对于代码：

textInput(DownDollars, "Downpayment (Dollars)", value = "", width = NULL, placeholder = NULL),

textInput(DownPercent, "Downpayment (Percent)", value = "", width = NULL, placeholder = NULL)

有没有办法使用这些输入的输出来代替value = 选项？

更新：以下是无法使用其他输入作为参考值的代码：

ui <- fluidPage(
  numericInput("HomePrice", "Home Price", value = ""),
  
  numericInput("DownPaymentDollars", "Down Payment (Dollars)", value = "", width = NULL),
  
  numericInput("DownPaymentPercent", "Down Payment (Percent)", value = "", width = NULL)
)

server = function(input, output, session){
  
  #referenceValue <- 254
  
  observeEvent(input$DownDollars, {
    updateNumericInput(session, "DownPaymentPercent", value = input$DownDollars * 100 / input$HomePrice)
  })
  
  observeEvent(input$DownPercent, {
    updateNumericInput(session, "DownPaymentDollars", value = input$DownPercent * input$HomePrice / 100)
  })
  
}

shinyApp(ui, server)

Answer 1

首先，使用numericInput获取数值更容易。以下代码可以满足您的需求：

library(shiny)


ui <- fluidPage(
  numericInput("DownDollars", "Downpayment (Dollars)", value = "", width = NULL),
  
  numericInput("DownPercent", "Downpayment (Percent)", value = "", width = NULL)
)

server = function(input, output, session){
  
  referenceValue <- 254
  
  observeEvent(input$DownDollars, {
    updateNumericInput(session, "DownPercent", value = input$DownDollars * 100 / referenceValue)
  })
  
  observeEvent(input$DownPercent, {
    updateNumericInput(session, "DownDollars", value = input$DownPercent * referenceValue / 100)
  })
  
}

shinyApp(ui, server)

我定义了一个referenceValue来计算百分比，你可以根据需要定义这个值，例如取自另一个用户输入。

小心使用引号定义输入 ID。

编辑

当使用另一个numericInput得到参考值时，需要观察这个新的numericInput来更新计算。两个updateNumericInput之一必须同时被两个observeEvent触发（见）：

library(shiny)


ui <- fluidPage(
  numericInput("HomePrice", "Home Price", value = ""),
  numericInput("DownDollars", "Downpayment (Dollars)", value = "", width = NULL),
  
  numericInput("DownPercent", "Downpayment (Percent)", value = "", width = NULL)
)

server = function(input, output, session){
  
  
  observeEvent({
    input$HomePrice
    input$DownDollars
    }, {
    updateNumericInput(session, "DownPercent", value = input$DownDollars * 100 / input$HomePrice)
  })
  
  observeEvent(input$DownPercent, {
    updateNumericInput(session, "DownDollars", value = input$DownPercent * input$HomePrice / 100)
  })
  
}

shinyApp(ui, server)

使用文本输入计算闪亮应用程序中另一个文本输入的值

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