Unnesting a list of lists in a data frame column
<p>To unnest a data frame I can use:</p>

<pre><code>df &lt;- data_frame(
    x = 1,
    y = list(a = 1, b = 2)
)

tidyr::unnest(df)
</code></pre>

<p>But how can I unnest a list inside of a list inside of a data frame column?</p>

<pre><code>df &lt;- data_frame(
    x = 1,
    y = list(list(a = 1, b = 2))
)
tidyr::unnest(df)
</code></pre>

<p>Error:</p>

<blockquote>
  <p>Each column must either be a list of vectors or a list of data frames [y]</p>
</blockquote>