R Shiny 中的相互依赖过滤器级联 - updatePickerInput

Question

我在 R Shiny 应用程序中有 4 个 PickerInputs，输出是这些输入的过滤数据帧。有时会选择这些输入，有时不会（意味着不应用任何过滤器）。

问题：我希望所有这些输入通过彼此的选择来级联。

column(width=2, id="filters",
       
       shinyWidgets::pickerInput(
         inputId = "filter_a",
         label = 'Filter A',
         choices = c(""),
         multiple = FALSE),
       
       shinyWidgets::pickerInput(
         inputId = "filter_b",
         label = 'Filter B',
         choices = c(""),
         multiple = FALSE),
       
       shinyWidgets::pickerInput(
         inputId = "filter_c",
         label = 'Filter C',
         choices = c(""),
         multiple = FALSE),
       
       shinyWidgets::pickerInput(
         inputId = "filter_d",
         label = 'Filter D',
         choices = c(""),
         multiple = FALSE)
       )

服务器：这些相互依赖的filter级联的if-else写法看起来不太好。它绝对不是优化的代码。我怎样才能把它写成一个函数？

我需要每个过滤器观察其他 3 个过滤器，并更新选择。

更新示例 'filter C':

observeEvent(c(input$filter_a, input$filter_b, input$filter_d),
             
             {updatePickerInput(session = session,
                                inputId = 'filter_c',
                                
                                choices = if(input$filter_a==" All" & input$filter_b == " All" & input$filter_d == " All"){sort(c(" All", unique(df$column_c)))
                                }else if(input$filter_a ==" All" & input$filter_b == " All" & input$filter_d != " All"){sort(c(" All", unique(df$column_c[df$column_d==input$filter_d])))
                                }else if(input$filter_a ==" All" & input$filter_b != " All" & input$filter_d == " All"){sort(c(" All", unique(df$column_c[df$column_b==input$filter_b])))
                                }else if(input$filter_a !=" All" & input$filter_b == " All" & input$filter_d == " All"){sort(c(" All", unique(df$column_c[df$column_a==input$filter_a])))
                                }else if(input$filter_a ==" All" & input$filter_b != " All" & input$filter_d != " All"){sort(c(" All", unique(df$column_c[df$column_b==input$filter_b & df$column_d==input$filter_d])))
                                }else if(input$filter_a !=" All" & input$filter_b == " All" & input$filter_d != " All"){sort(c(" All", unique(df$column_c[df$column_a==input$filter_a & df$column_d==input$filter_d])))
                                }else if(input$filter_a !=" All" & input$filter_b != " All" & input$filter_d == " All"){sort(c(" All", unique(df$column_c[df$column_a==input$filter_a & df$column_b==input$filter_b])))
                                }else{sort(c(" All", unique(df$column_c[df$column_a==input$filter_a & df$column_b==input$filter_b & df$column_d==input$filter_d])))},
                                selected = c(" All"))
             })

column_a、column_b、column_c 和 column_d 是我选择 filter_a、[=分别为 30=、filter_c、filter_d。

Answer 1

也许这样会好一点

observeEvent(c(input$filter_a, input$filter_b, input$filter_d), {
   
  if(input$filter_a==" All") {fa <- unique(df$column_a)} else fa <- input$filter_a
  if(input$filter_b==" All") {fb <- unique(df$column_b)} else fb <- input$filter_b
  if(input$filter_d==" All") {fd <- unique(df$column_d)} else fd <- input$filter_d

  choices <- c(" All", unique(df$column_c[df$column_a %in% fa & df$column_b %in% fb & df$column_d %in% fd]))
  updatePickerInput(session = session, inputId = 'filter_c', choices = choices, selected = c(" All"))

})

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