R Shiny, - Passing Multiple User Inputs into a single dataframe in server

Question

I must admit I am relatively new to R-Shiny so apologies if this is a very basic question.

I am trying to create an R-Shiny app which takes in user inputs in relation to an asset class' expected annual return, maximum weight and minimum weight. Ideally I would like to end up with a server dataframe similar to the below, with the expected returns and weights configurable:

Asset Class	Expected_Return	Max_Weight	Min_Weight
Equity	0.08	1.00	0.25
Bonds	0.02	0.75	0.10
Gold	0.03	0.20	0.00
Property	0.05	0.30	0.00
Cash	0.01	0.10	0.00

My UI code:

library(shiny)



ui <- fluidPage(
   fluidRow(
       column(width = 1, align="center",
              checkboxInput("equity_include", "Equity", value = TRUE, width = '100%')
       ),
       column(width = 5, align="center",
              numericInput("equity_er", "Global Expected Annual Return (%)", value = 0)
       ),
       column(width = 3, align="center",
              numericInput("equity_maxw", "Max Weight %", value = 100, min = 0, max = 100)
       ),
       column(width = 3, align="center",
              numericInput("equity_minw", "Min Weight %", value = 0, min = 0, max = 100)
       )
   ),
   fluidRow(
       column(width = 1, align="center",
              checkboxInput("bonds_include", "Bonds", value = TRUE, width = '100%')
       ),
       column(width = 5, align="center",
              numericInput("bonds_er", "Bonds Expected Annual Return (%)", value = 0)
       ),
       column(width = 3, align="center",
              numericInput("bonds_maxw", "Max Weight %", value = 100, min = 0, max = 100)
       ),
       column(width = 3, align="center",
              numericInput("bonds_minw", "Min Weight %", value = 0, min = 0, max = 100)
       )
   ),
   fluidRow(
       column(width = 1, align="center",
              checkboxInput("gold_include", "Gold", value = TRUE, width = '100%')
       ),
       column(width = 5, align="center",
              numericInput("gold_er", "Gold Expected Annual Return (%)", value = 0)
       ),
       column(width = 3, align="center",
              numericInput("gold_maxw", "Max Weight %", value = 100, min = 0, max = 100)
       ),
       column(width = 3, align="center",
              numericInput("gold_minw", "Min Weight %", value = 0, min = 0, max = 100)
       )
   ),
   fluidRow(
       column(width = 1, align="center",
              checkboxInput("property_include", "Property", value = TRUE, width = '100%')
       ),
       column(width = 5, align="center",
              numericInput("property_er", "Property Expected Annual Return(%)", value = 0)
       ),
       column(width = 3, align="center",
              numericInput("property_maxw", "Max Weight %", value = 100, min = 0, max = 100)
       ),
       column(width = 3, align="center",
              numericInput("property_minw", "Min Weight %", value = 0, min = 0, max = 100)
       )
   ),
   fluidRow(
       column(width = 1, align="center",
              checkboxInput("cash_include", "Cash", value = TRUE, width = '100%')
       ),
       column(width = 5, align="center",
              numericInput("cash_er", "Cash Expected Annual Return(%)", value = 0)
       ),
       column(width = 3, align="center",
              numericInput("cash_maxw", "Max Weight %", value = 100, min = 0, max = 100)
       ),
       column(width = 3, align="center",
              numericInput("cash_minw", "Min Weight %", value = 0, min = 0, max = 100)
       )
   ),
)

My Server Code:

server <- function(input, output) {
    library("tidyverse")
    library(plotly) # To create interactive charts
    library(timetk) # To manipulate the data series
    
    #Create Dataframe of User Inputs
    assets <- c("Equity", "Bonds", "Gold", "Property", "Cash")
    include <- c(input$equity_include, input$bonds_include, input$gold_include, input$property_include, input$cash_include)
    expected_return <- c(input$equity_er, input$bonds_er, input$gold_er, input$property_er, input$cash_er)
    max_weight <- c(input$equity_maxw, input$bonds_maxw, input$gold_maxw, input$property_maxw, input$cash_maxw)
    min_weight <- c(input$equity_minw, input$bonds_minw, input$gold_minw, input$property_minw, input$cash_minw)
    
    user_inputs <- data.frame(assets, include, expected_return, max_weight, min_weight)
   

Unfortunately I am getting multiple reactivity errors which I have been unable to resolve using the typical reactive() function.

I'd really appreciate any help you may be able to offer on this issue.

Thank you in advance!

Answer 1

I know answers are usually supposed to solve your specific problem but I am quite lazy to type all those defaults, you can do this with editable data frames, I like to use the DT package for this

example based on:https://yihui.shinyapps.io/DT-edit/

library(shiny)
library(DT)

dt_output = function(title, id) {
  fluidRow(column(
    12, h1(paste0('Table ', sub('.*?([0-9]+)$', '\\1', id), ': ', title)),
    hr(), DTOutput(id)
  ))
}
render_dt = function(data, editable = 'cell', server = TRUE, ...) {
  renderDT(data, selection = 'none', server = server, editable = editable, ...)
}

shinyApp(
  ui = fluidPage(
    title = 'Double-click to edit table rows',
    
    dt_output('server-side processing (editable = "row")', 'x6'),
  ),
  
  server = function(input, output, session) {
    d6 = iris
    d6$Date = Sys.time() + seq_len(nrow(d6))
    
    options(DT.options = list(pageLength = 5))
    
    # server-side processing
    output$x6 = render_dt(d6, 'row')
    
    # edit a row
    observeEvent(input$x6_cell_edit, {
      d6 <<- editData(d6, input$x6_cell_edit, 'x6')
    })
    
})