title: R data subset restructuring
body: <p>I am fairly new to R/Rstudio and I am still learning how to do certain operations.
  I have the following data set. For columns I have Operating Region, type of element(CA,OBU), sub-element and Net Revenue. 
  Currently the data is quite big(50 000 rows) and I want to get a summary of Operating region by element,sub-element and NR.
  Example</p>
  
  <pre><code> Operating Region   Element Sub-Element NR
   Asia        CA     CA123   50 000
   America    OBU     EFK456  35 000
  </code></pre>
  
  <p>Could someone please guide me on how to accomplish this? 
  Any relevant readings/examples would be much appreciated.</p>