Shiny values within a function from input

Question

I am working on a shiny app, where I need input values to show up in a function.

What I am trying to do is to somehow extract names and values from input, like CL=4, V1=3, and feed them in a function that I need to feed into a model in server later on. The model I am working on only takes function format. Below is my code.

UI:

#Set up
rm(list=ls())

library(shiny)
library(shinydashboard)
library(shinyBS)
library(dplyr)

#Design sidebar
sidebar <- dashboardSidebar(width = 200, collapsed=TRUE,
                            sidebarMenu(id="tabs",
                                        menuItem("Simulations", tabName = "Sims", icon = icon("line-chart"), selected=TRUE),
                                        menuItem("Placeholder", tabName = "Place", icon = icon("square-o"))
                            ))

#Design body 
body <- dashboardBody(
  tabItems(
    tabItem(tabName = "Sims", 
            box(collapsible=TRUE, width = 3, status = "success", solidHeader = T, title="Select Your Model",
                radioButtons(inputId="PK_Model", label = "PK Model", selected="One_Comp", 
                             choices = c("1 Compartment"="One_Comp", "2 Compartment"="Two_Comp")),
                radioButtons(inputId="Clearance_Model",label ="Clearance Mechanism", selected="Linear", 
                             choices = c("Linear"="Linear"))),
            box(collapsible=TRUE, status = "success", solidHeader = T, title="Enter Parameter Estimates", 
                        conditionalPanel(condition = "input.Clearance_Model == 'Linear'",
                                          numericInput(label="Clearance (Linear) (CL; L/day)", inputId="CL", min = 0, max = NA, value = 0),
                                          numericInput(label="Central volume of distribution (V1; L)", inputId="V1", min = 0, max = NA, value = 0)),
                         conditionalPanel(condition = "input.PK_Model == 'Two_Comp'",
                                          numericInput(label="Inter-compartment clearance (Q; L/day)", inputId="Q", min = 0, max = NA, value = 0),
                                          numericInput(label="Peripheral volume of distribution (V2; L)", inputId="V2", min = 0, max = NA, value = 0))),
              box(collapsible=T, width=2, status = "success", solidHeader = T, title="Run",
                actionButton('gosim','Run Sims',class='btn btn-info', icon=icon('play-circle-o','fg-lg'))), 
              box(width=5, status = "success", solidHeader = T, title="Simulated", textOutput('testprint')))))

#Show title and the page (includes sidebar and body)
dashboardPage(skin=c("blue"),
              dashboardHeader(titleWidth=900, title = "Shiny Test"),
              sidebar,  body)

UPDATED: Following PoGibas's answer below, I updated server code to following, but result does not look like what I need.

Server:

    library(shiny)
    library(shinydashboard)
    library(shinyBS)
    library(RxODE)
    library(parallel)
    library(ggplot2)

test <- function (N1, N2, N3, N4) {
  mypar <- function(lKa, lKdeg, N1, N2, N3, N4){
    Ka=exp(lKa)
    Kdeg=exp(lKdeg)
    V1=N1
    CL=N2
    Q=N3
    V2=N4}
  return(mypar)
}

    shinyServer(function(input, output, session){

 mypar <-eventReactive(input$goSimPH20, {
  N1=as.numeric(input$V1)
  N2=as.numeric(input$CL)
  N3=as.numeric(input$Q)
  N4=as.numeric(input$V2)
  par1 = test(N1, N2, N3, N4)
  return(par1)
})

        output$testprint <- renderText(mypar())  

        })

What I need result to look like when I call mypar() within server is as below:

test <- function (lKa, lKdeg, V1, CL, Q, V2) {
            Ka=exp(lKa)
            Kdeg=exp(lKdeg)
            V1=xx
            V2=xx
            CL=xx
            Q=xx
            }

xx can be any user supplied value in UI.

if my solution helped to solve your problem you can accept the answer so we can close the question :) — pogibas
– pogibas, Commented Sep 22, 2017 at 21:35
Please rewrite your code to be a minimal example. stackoverflow.com/help/mcve — parasietje
– parasietje, Commented Jan 17, 2018 at 10:35
@Krina can you please accept the answer if it helped to solve your problem? — pogibas
– pogibas, Commented Jan 17, 2018 at 11:02

pogibas · Accepted Answer · 2017-09-22 19:52:57Z

4

I simplified server part to this:

test <- function (V1 = 1, CL = 2, lA = 1, lB = 2) {
    return(lA + lB + V1 + CL)
}

shinyServer(function(input, output, session) {
    mypar <- reactive({
        V1 = as.numeric(input$V1)
        CL = as.numeric(input$CL)
        return(test(V1, CL))
    })
    output$testprint <- renderText(mypar())  
})

In test function add your wanted formula. User input is extracted using V1 = as.numeric(input$V1) and passed to test using test(V1, CL).

answered Sep 22, 2017 at 19:52

pogibas

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1 Comment

Krina M Over a year ago

thanks for your response. I am still struggling with this. What I need in return from calling mypar is a function that looks like below: test <- function (lA, lB,...) { A=exp(lA) B=exp(lB) V1=xx V2=xx CL=xx Q=xx } I tried several different ways using your suggested approach, but no luck yet.

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