title: Remove key from hash
body: <p>I have to remove all keys which are representing empty string for example</p>
  
  <pre><code>inventory = {"4"=&gt;"", "1"=&gt;"51059441", "3"=&gt;""}
  </code></pre>
  
  <p>And The result should be</p>
  
  <p>inventory = {"1"=>"51059441"}</p>