R shiny : checkboxGroupInput value

Question

I'm new to R and I have this code in Ui.R : ``` library(shiny) ui <- shinyUI(fluidPage( titlePanel("Test 1"), sidebarLayout( sidebarPanel( checkboxGroupInput("sex", "sex", c("Men", "Women")), textOutput("number") ), mainPanel( ) ) )) ``` And this code in Server.R : ``` server <- shinyServer(function(session, input, output) { observeEvent(input$sex, { if (input$sex == "Men"){s<-1} number<-as.numeric(s) if (input$sex == "Women"){s<-2} number<-as.numeric(s) if (input$sex == "Men" & input$sex == "Women"){s<-5} number<-as.numeric(s) if (is.null(input$sex)) {s<-10} number<-as.numeric(s) output$number<-renderText({number}) }) }) ``` So, I don't understand why "number" does not take value 5 when I check both check boxes, and why "number" does not take value 10 if I uncheck both boxes ? If you could help me to understand please. Thank you very much. EDIT : how to deselect checkboxGrouInput "dynamic" ? ``` library(shiny) ui <- shinyUI(fluidPage( titlePanel("Test 1"), sidebarLayout( sidebarPanel…

Accepted Answer

A few thing to consider in your code:

1) if both male and female are selected, then input$sex has length=2 (chr [1:2] "Men" "Women"). This line wont work.

```
(input$sex == "Men" & input$sex == "Women")
```

2) At app init input$sex is NULL, and you can not use a null in an if statement as in

```
if (input$sex == "Men") 
```

3) you dont need observeEvent. renderText is reactive to input$sex.

I made some changes to your code

```
library(shiny)

ui <- shinyUI(fluidPage(

titlePanel("Test 1"),

sidebarLayout(
    sidebarPanel(
      checkboxGroupInput(inputId = "sex", label = "sex",choices =  c("Men", "Women")),
      textOutput("number")
    ),

mainPanel()
  )
))

server <- shinyServer(function(session, input, output) {

output$number<-renderText({

if (is.null(input$sex) ){return(10)}

if (length(input$sex) ==1){
        if (input$sex == "Men"){
          s<-1
        } else if (input$sex == "Women"){
          s<-2
        }
    } else{
        return(5)
    }

return(as.numeric(s))
  })
})

shiny::shinyApp(ui, server)
```

update - if you have more options

```
library(shiny)

ui <- shinyUI(fluidPage(

titlePanel("Test 1"),

sidebarLayout(
    sidebarPanel(
      checkboxGroupInput(inputId = "sex", label = "sex",choices =  c("Men", "Women", "Children")),
      textOutput("number")
    ),

mainPanel()
  )
))

server <- shinyServer(function(session, input, output) {

output$number<-renderText({

if (is.null(input$sex) ){return(10)}

men      <- "Men"       %in% input$sex
    women    <- "Women"     %in% input$sex
    children <- "Children"  %in% input$sex

if (men & women & children){
      s <- 8 
    } else if (men & women){
      s <- 5
    } else if (men){
      s <-1
    } else if (women){
      s <-2
    } else if (children) {
      s <- 3
    }

return(as.numeric(s)) 
  })
})

shiny::shinyApp(ui, server)
```

R shiny : checkboxGroupInput value

Solution

Problem