title: how to order dictionary of dataframes by length
body: <p>I am trying to merge dataframes in a dictionary</p>
  <pre><code>example_dict = {key1: df1, key2: df2, ....}
  </code></pre>
  <p>each of the dataframes are of different row length, and all have a column called <code>id</code></p>
  <p>my plan was to do this:</p>
  <pre><code>merged_dfs = partial(pd.merge, on='id', how='inner')                                                              
  master_merged_dfs = reduce(merged_dfs, example_dict.values())
  </code></pre>
  <p>The issue is that some dataframes have few ids, and some have many. if I do an inner join the issue is that eventually the final merged df will keep getting smaller.</p>
  <p>I think the best way to go about this is probably order all the dataframes in the dictionary, then doing a left or right joing depending on if the ordering is ascending or descending.</p>
  <p>I just dont know how I would do the ordering.</p>