title: Knit error. Object not found
body: <p>I have an uncleaned <a href="https://i.stack.imgur.com/EDkXI.png" rel="noreferrer">dataset</a>. So, I have imported it to my R studio.Then when I run <code>nrow(adult)</code> in the rmarkdown file and press <code>ctrl+Enter</code> it works, but when i press the <code>knit</code> the following error appears:'</p>
  
  <p><a href="https://i.stack.imgur.com/EDkXI.png" rel="noreferrer"><img src="https://i.stack.imgur.com/EDkXI.png" alt="enter image description here"></a></p>