title: Retreiving individual values from a column with a list
body: <p>I have a dataframe with the twitter username, and the list of hashtags in a particular tweet. The hashtags column maybe a single tweet, a list of tweet or an empty tweet.</p>
  
  <pre><code>screenName      hashtags
  realDonaldTrump c("#1", "#2", "#2")
  realDonaldTrump character(0)
  realDonaldTrump #LaunchAmerica,
  realDonaldTrump #GeorgeFloyd
  realDonaldTrump c("#MinneapolisRiot", "#Coronavirus")
  </code></pre>
  
  <p>I want to get a list of individual hashtags against a username.</p>