title: Remove everything after a character, but keep the character
body: <p>Let's say I have a string that reads <code>"45216 Walnut Avenue Mary's Bake Shop"</code>. 
  I want to remove everything after the word <code>Avenue</code>, but I would like avenue to remain. How does this work?</p>
  
  <p>I've tried the following with no luck:</p>
  
  <pre><code>a &lt;- "45216 Walnut Avenue Mary's Bake Shop"
  a &lt;- gsub("Avenue.*$", "", a)
  
  [1] "45216 Walnut "
  </code></pre>