title: Display Date in ggplot as x axis
body: <p>My data has the format of </p>
  
  <pre><code>["201301",1111],["201302",1111],["201702",2222],["201603",3333].
  </code></pre>
  
  <p>However, when I try to plot it as a bar chart, it looks not nice since the x value was considered as a number. There is a large gap between years. 
  <a href="https://i.stack.imgur.com/VKdu4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VKdu4.png" alt="enter image description here"></a></p>
  
  <p>Is it possible to eliminate the gap?</p>