title: R: combine list of lists into a single dataframe
body: <p>I have a list (res) containing p x b number of dataframes. Each dataframe has 12 columns but varying number of rows (e.g, <code>res[[1]][[1]]</code> has 12 cols and 36 rows, but <code>res[[1]][[1]]</code> has 12 cols and 38 rows).
  I would like to combine them into a single dataframe that has 12 columns and 179 rows let's say. 
  The<code>do.call("rbind", listOfDataFrames)</code> method doesn't work as I loose column and row information. Let me know, if further specification is needed.
  Many thanks!</p>