How to create IF statement with reactive values in R ( Shiny )
<p>Beginner to R and shiny here!
Tried to make a minimal working example... I want to check a condition on a reactive input value. What am I doing wrong?</p>

<pre><code>library(shiny)

ui&lt;-fluidPage(

  numericInput(inputId="a", label=NULL, value=0),
  textOutput(outputId="out")
)

server &lt;- function(input, output) {
  x &lt;- reactive(input$a)
  if (x() &lt; 4) 
    {y&lt;-1}
  else
  {y&lt;-0}

  output$out &lt;- renderText({y})
}

shinyApp(ui = ui, server = server)
</code></pre>

<p>The error message: </p>

<blockquote>
  <p>Operation not allowed without an active reactive context. (You tried
  to do something that can only be done from inside a reactive
  expression or observer.)</p>
</blockquote>