      a     b c     d     e     f          g                   h        
  <dbl> <int> <lgl> <chr> <fct> <date>     <dttm>              <list>   
1   1       1 TRUE  a     a     2015-12-10 2015-12-09 10:51:35 <int [1]>
2   2.5     2 FALSE b     b     2015-12-11 2015-12-09 10:51:36 <int [1]>
3  NA      NA NA    <NA>  <NA>  NA         NA                  <int [1]>
  i         
  <list>    
1 <list [2]>
2 <list [1]>
3 <list [1]>
