如何摆脱 R shiny 中的某个列？

Question

我想通过使用 selectInput in R shiny 到 select 列名称来删除列。为此，我构建了函数“removecolumn”，它将“nameofthecolumn”作为参数并删除指定的列。我使用 observeEvent 在服务器代码中调用该函数，但它不起作用并给我以下错误。

有人可以帮助我解决这个问题，并指出任何资源，我可以从中学习如何将动态列名调用到任何服务器函数中吗？

错误

Warning: Error in removecolumn: unused argument (input$selectcolumn)

csv 数据

ID  Type   Range
21  A1 B1   100
22  C1 D1   200
23  E1 F1   300

代码概述 基本上，代码接受 CSV 文件作为输入，并且根据问题，我在应用程序中使用“SplitColumns”、“删除行”和“替换值”按钮，但是，我想添加另一个名为“立即删除列。

app.R

library(shiny)
library(reshape2)
#source('splitColumn_stack.R')
library(DT)
library(tibble)


###function for deleting the rows
splitColumn <- function(data, column_name) {
  newColNames <- c("Unmerged_type1", "Unmerged_type2")
  newCols <- colsplit(data[[column_name]], " ", newColNames)
  after_merge <- cbind(data, newCols)
  after_merge[[column_name]] <- NULL
  after_merge
}
###_______________________________________________
### function for inserting a new column

fillvalues <- function(data, values, columName){
  df_fill <- data
  vec <- strsplit(values, ",")[[1]]
  df_fill <- tibble::add_column(df_fill, newcolumn = vec, .after = columName)
  df_fill
}

##function for removing the colum
removecolumn <- function(nameofthecolumn){
  df[ , -which(names(df) %in% nameofthecolumn)]
  
}

### use a_splitme.csv for testing this program

ui <- fluidPage(
  sidebarLayout(
    sidebarPanel(
      fileInput("file1", "Choose CSV File", accept = ".csv"),
      checkboxInput("header", "Header", TRUE),
      actionButton("Splitcolumn", "SplitColumn"),
      selectInput(inputId='selectcolumn', label='select column', ''),
      actionButton("deleteRows", "Delete Rows"),
      textInput("textbox", label="Input the value to replace:"),
      actionButton("replacevalues", label = 'Replace values'),
      actionButton("removecolumn", "Remove Column")
    ),
    mainPanel(
      DTOutput("table1")
    )
  )
)

server <- function(session, input, output) {
  rv <- reactiveValues(data = NULL)
  
  observeEvent(input$file1, {
    file <- input$file1
    ext <- tools::file_ext(file$datapath)
    
    req(file)
    
    validate(need(ext == "csv", "Please upload a csv file"))
    
    rv$data <- read.csv(file$datapath, header = input$header)
    
    updateSelectInput(session, 'selectcolumn', 'select column', names(rv$data))
    
  })
  
  observeEvent(input$Splitcolumn, {
    rv$data <- splitColumn(rv$data, input$selectcolumn)
  })
  
  observeEvent(input$deleteRows,{
    if (!is.null(input$table1_rows_selected)) {
      rv$data <- rv$data[-as.numeric(input$table1_rows_selected),]
    }
  })
  
  output$table1 <- renderDT({
    rv$data
  })
  observeEvent(input$replacevalues, {
    rv$data <- fillvalues(rv$data, input$textbox, input$selectcolumn)
  })
  observeEvent(input$removecolumn, {
    rv$data <- removecolumn(rv$data,input$selectcolumn)
  })
}

shinyApp(ui, server)

Answer 1

您忘记了函数中的参数 df removecolumn:

##function for removing the column
removecolumn <- function(df, nameofthecolumn){
  df[ , -which(names(df) %in% nameofthecolumn)]
}

如何摆脱 R shiny 中的某个列？

How do I get rid of a certain column in R shiny?

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