      a     b c    
  <dbl> <int> <lgl>
1  1.00     1 T    
2  2.50     2 F    
3 NA       NA NA   
  d     e     
  <chr> <fctr>
1 a     a     
2 b     b     
3 <NA>  <NA>  
  f         
  <date>    
1 2015-12-10
2 2015-12-11
3 NA        
