title: ggplot - Custom format for plot axis of time variable
body: <p>How to define custom format for time variable axis in <a href="/questions/tagged/ggplot2" class="post-tag" title="show questions tagged &#39;ggplot2&#39;" rel="tag">ggplot2</a>?</p>
  
  <pre><code>DF &lt;- data.frame(TIME = c(350,400,250,650,500,750),
                   CATEGORY = c(1:6))
  
  
  ggplot(data=DF, aes(x=CATEGORY, y=as_datetime(TIME))) +
    geom_col() +
    scale_y_datetime(labels = date_format("%M:%S"))
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/KNiEZ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KNiEZ.png" alt="image"></a></p>
  
  <p>What I want is to remove leading zero at the minute-part. Something like this:</p>
  
  <p><a href="https://i.stack.imgur.com/GDpfa.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GDpfa.png" alt="image2"></a></p>
  
  <p>Thanks for your time &amp; effort!</p>