title: update values in numericInput R shiny
body: <p>I have an app wherein users can input numeric values for certain fields (using <code>numericInput()</code>). Alternatively, they can choose to select values from a reference table (via a <code>checkboxInput()</code> field). </p>
  
  <p>I'm able to code this behaviour in the script properly. But I also want that if the <code>checkboxInput</code> field is selected, the values displayed in the <code>numericInput()</code> get updated i.e. the default values or previously written values are overwritten. </p>
  
  <p><a href="https://i.stack.imgur.com/yOgoU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yOgoU.png" alt="enter image description here"></a></p>
  
  <p>In the screenshot, the  <code>numericInput</code> fields are highlighted in yellow. The top field has a default value of 14 whereas the others are empty. I want that the if the "Copy reference values?" <code>checkboxInput</code> is selected, the copied values get displayed in the corresponding fields (k1 = 72.49 for "Flow Coef. for dP" etc.)  </p>
  
  <p>My code is as below: </p>
  
  <pre><code>fluidRow(
      column(4,
             numericInput(inputId = "Area", 
                          label = tags$div(HTML(paste("rea (m", tags$sup(2), ")", sep = ""))),
                          min = 1, max = 100, step = 0.1, value = 14),
             numericInput(inputId = "k1", label = "Flow coef. for dP", min = 1.0, max = 600.0, value = ""),
             numericInput(inputId = "k2", label = "Flow exponent for dP" , min = 1.0, max = 20.0, value = "")
             checkboxInput("copyVals", "Copy Reference Values?", value = FALSE)
  )
  </code></pre>