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