title: Combine DataFrames with an array column
body: <p>There are 2 DataFrames, df1 is defined as </p>
  
  
  
  <pre class="lang-none prettyprint-override"><code> +----+---------+---------+
   |id  |value1   |value2   | 
   +----+---------+---------+
   |1   |["J","W"]|      0.3|
   |2   |         |      0.6|
   |3   |["n"]    |      0.7|
   +----+---------+---------+
  </code></pre>
  
  <p>df2 is defined as </p>
  
  <pre class="lang-none prettyprint-override"><code> +----+---------+
   |id  |value1   |
   +----+---------+
   | 1  | "t"     |
   | 2  | "m"     |
   +----+---------+
  </code></pre>
  
  <p>is there an easy way to combine the DataFrame as df3</p>
  
  <pre class="lang-none prettyprint-override"><code> +----+--------------+---------+
   |id  |value1        |value2   | 
   +----+--------------+---------+
   |1   |["J","W", "t"]|      0.3|
   |2   |["m]          |      0.6|
   |3   |["n"]         |      0.7|
   +----+--------------+---------+
  </code></pre>