as_reliable             Reliable conversion to another data type
convert                 Convert data type of columns
could_this_be_that      Tests is a vector could be of another data type
rationalize             Only allow rational values in numeric vectors
                        'rationalize' transforms all numeric elements
                        to be rational values or NA, thus removes all
                        'NaN,Inf' and replaces them with 'NA'.
retype                  Return simple data types
s                       Make vector shorter and simpler
wrapper - s and summary funs
                        Combine aggregate function and s
