title: Shiny - Input Argument Not Accessible
body: <p>I'm trying to take input from a slider in shiny and use it in the server section by calling a function on it to obtain information for graphing. However, the input from the slider is not recognized serverside, and throws an error.</p>
  
  <blockquote>
    <p>Evaluation error: argument "hour" is missing, with no default.</p>
  </blockquote>
  
  <p>The <code>inputID</code> matches the argument so I don't understand why it wouldn't be able to access it.</p>
  
  <pre><code>library(shiny)
  library(shinydashboard)
  get_data &lt;- function(foo){return(foo)}
  
  #build shiny app
  header &lt;- dashboardHeader(
              title="Data"
            )
  sidebar &lt;- dashboardSidebar(
    sidebarMenu(
      menuItem("Charts and Analysis", tabName = "charts", icon = icon("bar-chart-o"), 
               menuSubItem("Temperature by Time of Day", tabName = "temperatures", icon = NULL)        )        
    )
  )
  
  body &lt;- dashboardBody(
    tabItems(
      tabItem(tabName = "temperatures",
        fluidRow(
          box(
              title = "Time of Day",
              sliderInput(inputId = "hour", label="Hour (military)", min=0, max=23, value=12, step=1)
          ),
          box(plotOutput("series"))
        )
      )
  
  
    )
  
  
  )
  
  
  ui &lt;- dashboardPage(skin="green", header, sidebar, body)
  server &lt;- function(input, output) { 
  
    MR &lt;- get_data(strtoi(input$hour))
    output$series &lt;- renderPlot({
      plot(x=MR, y=MR) 
     })
  }
  
  shinyApp(ui, server)
  </code></pre>