反应值内的反应环境（RShiny）

我正在尝试构建一个带有反应维度的矩阵，我希望使用observeEvent表达式更新该矩阵。我的想法如下：

library(shiny)

ui <- fluidPage(
  numericInput("length", "Dimensions of the matrix", value = 5),
  numericInput("a", "value for a", value = 2),
  numericInput("b", "value for b", value = 2),
  numericInput("ind1", "value for index vector 1", value = 1),
  numericInput("ind2", "value for index vector 2", value = 1),
  actionButton("go", "Update"),
  tableOutput("matrix")
)

server <- function(input, output) {
  ### Calculate the value that will be used for the update
  value <- reactive(mean(rbeta(100, input$a, input$b)))

  ### Create a reactive index vector used to determine the position of the cell in the matrix
  ind <- reactive(c(input$ind1, input$ind2))

  beta.matrix <- reactiveValues(mat = NULL)
  beta.matrix.ini <- reactive({
    mat = matrix(0, input$length, input$length)
  })

  observe({
    beta.matrix$mat <- beta.matrix.ini()
  })

  ### Update matrix at positon ind with new value
  observeEvent(input$go, {
    beta.matrix$mat[ind()[1], ind()[2]] <- value()
  })

  ### Render matrix
  output$matrix <- renderTable({
    mat <- beta.matrix$mat
    mat
  })

}

# Run the application
shinyApp(ui = ui, server = server)

首先，我创建了一个reactiveValues对象，它有一个维度矩阵，输入$length（->reactive）和输入0。然后我使用observeEvent和actionButton来触发矩阵中的更新。这需要使用反应值（value（））更新矩阵中由反应索引向量（ind（））表示的特定单元格

我理解这个问题：在mat=。。。我不能使用另一个反应式表达式，但我没有其他解决方案，非常感谢您对此的任何意见

提前谢谢

亲切问候,

朱利安

---

---

ui我认为您需要两个反应性“阶段”

当尺寸更改时，初始化空矩阵
对矩阵内容的更改作出反应
请检查以下内容：

library(shiny)

ui <- fluidPage(
  numericInput("length", "Dimensions of the matrix", value = 5),
  numericInput("a", "value for a", value = 2),
  numericInput("b", "value for b", value = 2),
  numericInput("ind1", "value for index vector 1", value = 1),
  numericInput("ind2", "value for index vector 2", value = 1),
  actionButton("go", "Update"),
  tableOutput("matrix")
)

server <- function(input, output) {
  ### Calculate the value that will be used for the update
  value <- reactive(mean(rbeta(100, input$a, input$b)))

  ### Create a reactive index vector used to determine the position of the cell in the matrix
  ind <- reactive(c(input$ind1, input$ind2))

  beta.matrix <- reactiveValues(mat = NULL)
  beta.matrix.ini <- reactive({
    mat = matrix(0, input$length, input$length)
  })

  observe({
    beta.matrix$mat <- beta.matrix.ini()
  })

  ### Update matrix at positon ind with new value
  observeEvent(input$go, {
    beta.matrix$mat[ind()[1], ind()[2]] <- value()
  })

  ### Render matrix
  output$matrix <- renderTable({
    mat <- beta.matrix$mat
    mat
  })

}

# Run the application
shinyApp(ui = ui, server = server)

库（闪亮）
ui我认为这里需要两个反应“阶段”

当尺寸更改时，初始化空矩阵
对矩阵内容的更改作出反应
请检查以下内容：

library(shiny)

ui <- fluidPage(
  numericInput("length", "Dimensions of the matrix", value = 5),
  numericInput("a", "value for a", value = 2),
  numericInput("b", "value for b", value = 2),
  numericInput("ind1", "value for index vector 1", value = 1),
  numericInput("ind2", "value for index vector 2", value = 1),
  actionButton("go", "Update"),
  tableOutput("matrix")
)

server <- function(input, output) {
  ### Calculate the value that will be used for the update
  value <- reactive(mean(rbeta(100, input$a, input$b)))

  ### Create a reactive index vector used to determine the position of the cell in the matrix
  ind <- reactive(c(input$ind1, input$ind2))

  beta.matrix <- reactiveValues(mat = NULL)
  beta.matrix.ini <- reactive({
    mat = matrix(0, input$length, input$length)
  })

  observe({
    beta.matrix$mat <- beta.matrix.ini()
  })

  ### Update matrix at positon ind with new value
  observeEvent(input$go, {
    beta.matrix$mat[ind()[1], ind()[2]] <- value()
  })

  ### Render matrix
  output$matrix <- renderTable({
    mat <- beta.matrix$mat
    mat
  })

}

# Run the application
shinyApp(ui = ui, server = server)

库（闪亮）
用户界面