dplyr过滤器从data.frame返回所有

Question

我有一个selectInput函数，当用户选择“所有大学”时，我希望dplyr::filter返回所有值。它被传递了一个数据文件，所以dplry::if_else出错了。

    sidebarLayout(
        sidebarPanel(
          selectInput("university", 
                     "Select University",
                     choices = list("All Universities" = "all", "UAA" = "uaa", "UAF" = "uaf", "UAS" = "uas"),
                     multiple = F
          ),
        width = 2),

这是我的闪亮表输出函数

   output$headcountTable <- function(){
     enroll_report |>
      dplyr::filter(struc_uni == input$university)|>
      dplyr::select(-struc_uni) |>
      dplyr::select(-struc_code) |>
      kbl(booktabs = T,
        col.names = c("Campus", 
                     "Fall 2021", 
                     "Fall 2022",
                     "Change",
                     "%",
                     "Fall 2021", 
                     "Fall 2022",
                     "Change",
                     "%"),
        caption = "holder text") |>
      add_header_above(c("", "Headcount" = 4, "Credit Hours" = 4)) |>
      kable_styling("striped", 
               full_width = T, 
               position = "left", 
               font_size = 12)
   }

Answer 1

以下是John的解决方案的“在线”版本。它看起来有点奇怪，因为您使用的是|>管道，它没有位置保持器，所以我使用()()结构和\()匿名函数定义了一个。

output$headcountTable <- function(){
     enroll_report |>
      (\(d) if(input$university == "all") d 
       else dplyr::filter(d, struc_uni == input$university))() |>
      dplyr::select(-struc_uni) |>
      dplyr::select(-struc_code) |>
      kbl(booktabs = T,
        col.names = c("Campus", 
                     "Fall 2021", 
                     "Fall 2022",
                     "Change",
                     "%",
                     "Fall 2021", 
                     "Fall 2022",
                     "Change",
                     "%"),
        caption = "holder text") |>
      add_header_above(c("", "Headcount" = 4, "Credit Hours" = 4)) |>
      kable_styling("striped", 
               full_width = T, 
               position = "left", 
               font_size = 12)
   }

Answer 2

您可以隔离过滤它的代码，并使用简单的if检查它。

注意:只有当这种情况是孤立的.时，这才有效。

if(input$university != "all"){
    enroll_report <- enroll_report %>% 
      dplyr::filter(struct_uni == input$university)
}

enroll_report |>
  dplyr::select(-struc_uni) |>
  dplyr::select(-struc_code) |>
  kbl(booktabs = T,
  col.names = c("Campus", 
                "Fall 2021", 
                "Fall 2022",
                "Change",
                "%",
                "Fall 2021", 
                "Fall 2022",
                "Change",
                "%"),
  caption = "holder text") |>
  add_header_above(c("", "Headcount" = 4, "Credit Hours" = 4)) |>
  kable_styling("striped", 
            full_width = T, 
            position = "left", 
            font_size = 12)