Non-numeric argument to binary operator in Shiny

Question

I need some help I'm a newbie in Shiny world and stuck in something that might be very basic. Here's my ui.R and server.R code

shinyUI(
  pageWithSidebar(
    headerPanel("Hello Shiny R..."), 
    sidebarPanel(
      sliderInput(inputId="age", label="Age", min=1, max=99, value=24, step=1, animate=TRUE),
      numericInput(inputId="height", label="Height (cm)", min=0, max=300, value=160, step=5),
      numericInput(inputId="weight", label="Weight (kg)", min=0, max=500, value=100, step=5),
      radioButtons(inputId="gender", label="Gender", choices=c("Male", "Female"), selected="Male", inline=TRUE),
      textInput(inputId="name", label="Full Name"),
      submitButton(text="Apply")
    ),
    mainPanel(
      h1("BMI Calculator"),
      p("Name:"),
      textOutput("name"),
      p("Age:"),
      textOutput("age"),
      p("Gender:"),
      textOutput("gender"),
      p("BMI:"),
      textOutput("bmi")
    )
  )
)

shinyServer(
  function(input, output) {
    output$name <- renderText({input$name})
    output$age <- renderText({input$age})
    output$gender <- renderText({input$gender})
    weight <- renderText({as.numeric(input$weight)})
    height <- renderText({as.numeric(input$height)})
    output$bmi <- weight / (height * height)
  }
)

When I execute runApp(), here's what I'm getting:

Error in height * height : non-numeric argument to binary operator

seekme_94 seekme_94 · Accepted Answer · 2016-04-04T06:50:40

Ok! I solved this specific case by replacing render with reactive function.

weight <- reactive({input$
height <- reactive({input$height / 
output$bmi <- renderText({weight() / (height() * height())})

But this doesn't explain what's wrong with renderText function.

Non-numeric argument to binary operator in Shiny

1 Answers