title: Extract url from character strings
body: <p>I have a vector of characters</p>
  
  <p><a href="https://i.stack.imgur.com/2PxKW.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2PxKW.png" alt="enter image description here"></a></p>
  
  <p>I was wondering how to extract just the urls in each character string. I've tried the following, which kinda works, but is not perfect. </p>
  
  <pre><code>sub(".*http", "", character_string)
  </code></pre>
  
  <p>Ideally, I would like to extract out the url and nothing more or less.</p>