如何让之前有效的数据table转置，重启电脑后又有效？

Question

在下面的可重现代码中，单击单选按钮转置数据 table 工作正常，直到我重新启动计算机。现在post-重新启动，此应用程序在尝试转置时崩溃。可能之前在内存中加载了一个包或某个对象，使它能够工作。我试过找到这个丢失的物体，但还没有找到运气。无论如何，我怎样才能点击单选按钮（如底部图像所示）来转置数据 table?

此 post 是的后续解决方案，其解决方案运行良好（但不再有效）。

可重现代码（从上面引用的 post 缩短）：

library(DT)
library(shiny)
library(dplyr)
library(htmltools)
library(data.table)

data <- 
  data.frame(
    ID = c(1,1,1,2,2,2,3,3,3),
    Period = c(1, 2, 3, 1, 2, 3, 1, 2, 3),
    Values = c(5, 10, 15, 0, 2, 4, 3, 6, 9),
    State = c("X0","X1","X2","X0","X2","X0", "X2","X1","X0")
  )

numTransit <- function(x, from=1, to=3){
  setDT(x)
  unique_state <- unique(x$State)
  all_states <- setDT(expand.grid(list(from_state = unique_state, to_state = unique_state)))
  dcast(x[, .(from_state = State[from], 
              to_state = State[to]), 
          by = ID]
        [,.N, c("from_state", "to_state")]
        [all_states,on = c("from_state", "to_state")], 
        to_state ~ from_state, value.var = "N"
  )
}

ui <- fluidPage(
  tags$head(tags$style(".datatables .display {margin-left: 0;}")), 
  h4(strong("Base data frame:")), 
  tableOutput("data"),
  h4(strong("Transition table inputs:")),
  numericInput("transFrom", "From period:", 1, min = 1, max = 3),
  numericInput("transTo", "To period:", 2, min = 1, max = 3),
  radioButtons("transposeDT",
               label = "Transpose table:",
               choiceNames = c('Columns','Rows'),
               choiceValues = c('Columns','Rows'),
               selected = 'Columns',
               inline = TRUE
  ),
  h4(strong("Output transition table:")), 
  DTOutput("resultsDT"),
)

server <- function(input, output, session) {
  results <- 
    reactive({
      results <- numTransit(data, input$transFrom, input$transTo)
    })
  
  output$data <- renderTable(data)
  
  output$resultsDT <- renderDT(server=FALSE, {
    datatable(
      data = 
      # the line immediately below causes the app to crash when transposing the data table
        if(input$transposeDT=='Rows'){results()%>%transpose(make.names = 'to_state',keep.names = 'to_state')}
        else {results()},
      rownames = FALSE,
      filter = 'none',
      class = "display"
    ) %>%
      formatStyle(c(1), `border-right` = "solid 1px")
  })
}

shinyApp(ui, server)

Answer 1

YBS 评论（尝试 data.table::transpose(...)）解决了问题。见postWhat are the double colons (::) in R?，里面解释了可能存在多个包中的同名函数（我用transpose()好像就是这种情况）。双冒号运算符 :: 允许您指定特定包中的特定函数以在特定情况下使用。

如何让之前有效的数据table转置，重启电脑后又有效？

How to make data table transposition that previously worked, work again after a computer restart?

r

shiny

data.table

transpose