R Shiny: How to dynamically append arbitrary number of input widgets

Question

The goal

I am working on a Shiny app that allows the user to upload their own data and focus on the entire data or a subset by providing data filtering widgets describ

Answer 1

If you are looking for a data subsetting/filtering in Shiny Module :

filterData from package shinytools can do the work. It returns an expression as a call but it can also return the data (if your dataset is not too big).

library(shiny)
# remotes::install_github("ardata-fr/shinytools")
library(shinytools)

ui <- fluidPage(
  fluidRow(
    column(
      3,
      filterDataUI(id = "ex"),
      actionButton("AB", label = "Apply filters")
    ),
    column(
      3,
      tags$strong("Expression"),
      verbatimTextOutput("expression"),
      tags$br(),
      DT::dataTableOutput("DT")
    )
  )
)

server <- function(input, output) {

  x <- reactive({iris})

  res <- callModule(module = filterDataServer, id = "ex", x = x, return_data = FALSE)

  output$expression <- renderPrint({
    print(res$expr)
  })

  output$DT <- DT::renderDataTable({
    datatable(data_filtered())
  })

  data_filtered <- eventReactive(input$AB, {
    filters <- eval(expr = res$expr, envir = x())
    x()[filters,]

  })
}

shinyApp(ui, server)

You can also use lazyeval or rlang to evaluate the expression :

filters <- lazyeval::lazy_eval(res$expr, data = x())
filters <- rlang::eval_tidy(res$expr, data = x())