在 R 中，为什么我得到 "Error in [: (subscript) logical subscript too long"？

Question

下面的 MWE 代码 1 工作正常，在计算 2 列数字的和积时，sumproduct 输入矩阵水平扩展以适应额外的 sumproduct 场景。

下面的 MWE 代码 2 是对 MWE 代码 1 的修改，使输入矩阵也可以垂直扩展，因此用户可以在 sumproduct 计算中添加要求和的元素行。当我运行 MWE 代码 2 时，代码崩溃给我“Error in [: (subscript) logical subscript too long”。

为什么会出现此错误？

下图说明了这个问题。

MWE 代码 1：

library(shiny)
library(shinyMatrix)
library(dplyr)
library(ggplot2)

sumProd <- function(a, b) { # a = periods, b = matrix inputs
  c    <- rep(NA, a)
  c[]  <- sum(b[,1]) %*% sum(b[,2])
  return(c)
}

ui <- fluidPage(
  sliderInput('periods', 'X-axis periods:', min=1, max=10, value=10),
  matrixInput(
    "myMatrixInput",
    label = "Two columns to sumproduct are paired under each scenario heading:",
    value =  matrix(c(1, 5), 1, 2, dimnames = list(NULL, rep("Scenario 1", 2))),
    cols = list(extend = TRUE,  delta = 2, names = TRUE,  delete = TRUE, multiheader = TRUE),
    rows = list(extend = FALSE, delta = 1, names = FALSE, delete = FALSE),
    class = "numeric"),
  plotOutput("plot")
)

server <- function(input, output, session) {
  
  observeEvent(input$myMatrixInput, {
    tmpMatrix <- input$myMatrixInput
    
    # Remove any empty matrix columns
    empty_columns <- sapply(tmpMatrix, function(x) all(is.na(x) | x == ""))
    tmpMatrix <- tmpMatrix[, !empty_columns, drop=FALSE]
    
    # Assign column header names
    colnames(tmpMatrix) <- paste("Scenario", rep(1:ncol(tmpMatrix), each = 2, length.out = ncol(tmpMatrix)))
    
    isolate( # isolate update to prevent infinite loop
      updateMatrixInput(session, inputId = "myMatrixInput", value = tmpMatrix)
    )
  })
  
  plotData <- reactive({
    tryCatch(
      lapply(seq_len(ncol(input$myMatrixInput)/2),
             function(i){
               tibble(
                 Scenario = colnames(input$myMatrixInput)[i*2-1],
                 X = seq_len(input$periods),
                 Y = sumProd(input$periods,input$myMatrixInput[1,(i*2-1):(i*2), drop = FALSE])
               )
             }) %>% bind_rows(),
      error = function(e) NULL
    )
  })
  
  output$plot <- renderPlot({
    req(plotData())
    plotData() %>% ggplot() + geom_line(aes(
      x = X,
      y = Y,
      colour = as.factor(Scenario)
    ))
  })
  
}

shinyApp(ui, server)

MWE 代码 2：

sumProd <- function(a, b) { # a = periods, b = matrix inputs
  c    <- rep(NA, a)
  c[]  <- sum(b[,1]) %*% sum(b[,2])
  return(c)
}

ui <- fluidPage(
  sliderInput('periods', 'X-axis periods:', min=1, max=10, value=10),
  matrixInput(
    "myMatrixInput",
    label = "Two columns to sumproduct are paired under each scenario heading:",
    value =  matrix(c(1, 5), 1, 2, dimnames = list(NULL, rep("Scenario 1", 2))),
    cols = list(extend = TRUE,  delta = 2, names = TRUE,  delete = TRUE, multiheader = TRUE),
    rows = list(extend = TRUE, delta = 1, names = FALSE, delete = FALSE),
    class = "numeric"),
  plotOutput("plot")
)

server <- function(input, output, session) {
  
  sanitizedMat <- reactiveVal() # < for vertical matrix expansion
  
  observeEvent(input$myMatrixInput, {
    if(any(colnames(input$myMatrixInput) == "")){
      tmpMatrix <- input$myMatrixInput
      
      # Remove any empty matrix columns
      empty_columns <- sapply(tmpMatrix, function(x) all(is.na(x) | x == ""))
      tmpMatrix <- tmpMatrix[, !empty_columns, drop=FALSE]
      
      # Assign column header names
      colnames(tmpMatrix) <- paste("Scenario", rep(1:ncol(tmpMatrix), each = 2, length.out = ncol(tmpMatrix)))
      
      isolate( # isolate update to prevent infinite loop
        updateMatrixInput(session, inputId = "myMatrixInput", value = tmpMatrix)
      )
    }
    sanitizedMat(na.omit(input$myMatrixInput))
  })
  
  plotData <- reactive({
    tryCatch(
      lapply(seq_len(ncol(sanitizedMat())/2),
             function(i){
               tibble(
                 Scenario = colnames(sanitizedMat())[i*2-1],
                 X = seq_len(input$periods),
                 Y = sumProd(input$periods,sanitizedMat()[,(i*2-1):(i*2), drop = FALSE])
               )
             }) %>% bind_rows(),
      error = function(e) NULL
    )
  })
  
  output$plot <- renderPlot({
    req(plotData())
    plotData() %>% ggplot() + geom_line(aes(
      x = X,
      y = Y,
      colour = as.factor(Scenario)
    ))
  })
  
}

shinyApp(ui, server)

Answer 1

解决方案是简单地消除单个 observeEvent() 下的自动矩阵空列删除并修改 UDF sumProd() 以忽略 NA（添加 na.rm = T 到 sum() in sumProd()).当 sub-columns（每种情况下 2 列的分组 header）长度不等时，NA 将出现在矩阵中，因此忽略 NA 可以解决问题。还删除了 MWE2 中的 UDF sanitizedMat() 和自动空列删除功能以简化。

修改后的代码：

library(shiny)
library(shinyMatrix)
library(dplyr)
library(ggplot2)

sumProd <- function(a, b) { # a = periods, b = matrix inputs
  c    <- rep(NA, a)
  c[]  <- sum(b[,1], na.rm = T) %*% sum(b[,2],na.rm = T) # Added na.rm = T
  return(c)
}

ui <- fluidPage(
  sliderInput('periods', 'X-axis periods:', min=1, max=10, value=10),
  matrixInput(
    "myMatrixInput",
    label = "Two columns to sumproduct are paired under each scenario heading:",
    value =  matrix(c(1, 5), 1, 2, dimnames = list(NULL, rep("Scenario 1", 2))),
    cols = list(extend = TRUE,  delta = 2, names = TRUE,  delete = TRUE, multiheader = TRUE),
    rows = list(extend = TRUE, delta = 1, names = FALSE, delete = FALSE),
    class = "numeric"),
  plotOutput("plot")
)

server <- function(input, output, session) {
  
  observeEvent(input$myMatrixInput, {
    if(any(colnames(input$myMatrixInput) == "")){
      tmpMatrix <- input$myMatrixInput
      colnames(tmpMatrix) <- paste("Scenario",rep(1:ncol(tmpMatrix),each=2,length.out=ncol(tmpMatrix)))
      isolate(updateMatrixInput(session, inputId = "myMatrixInput", value = tmpMatrix))
      }
    input$myMatrixInput
  })
  
  plotData <- reactive({
    tryCatch(
      lapply(seq_len(ncol(input$myMatrixInput)/2), # column counter to set matrix index as it expands
         function(i){
             tibble(
               Scenario = colnames(input$myMatrixInput)[i*2-1],
               X = seq_len(input$periods),
               Y = sumProd(input$periods,input$myMatrixInput[,(i*2-1):(i*2), drop = FALSE])
             )
          }) %>% bind_rows(),
      error = function(e) NULL
    )
  })
  
  output$plot <- renderPlot({
    req(plotData())
    plotData() %>% ggplot() + geom_line(aes(
      x = X,
      y = Y,
      colour = as.factor(Scenario)
    ))
  })
  
}

shinyApp(ui, server)

在 R 中，为什么我得到 "Error in [: (subscript) logical subscript too long"？

In R, why am I getting "Error in [: (subscript) logical subscript too long"?

r

matrix

lapply

shiny

tibble