title: How to get number of matched elements in exactrors(Json/css/xpath)
body: <p>As you cans see, it is a JSON extractor element in JMeter and we can find BookName elements. 
  Question is, how to find total matched elements?</p>
  
  <p><a href="https://i.stack.imgur.com/EBZZZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/EBZZZ.png" alt="enter image description here"></a></p>