coalesce                Return first non-missing element
columns                 Selects columns or rows from the data set
copy                    Copy an entire object
dt_count                Additional useful functions
dt_left_join            Join two data.frames by common columns.
dt_mutate               'dplyr'-like interface for data.table.
let_if                  Modify, aggregate, select or filter
                        data.frame/data.table
maditr-package          maditr: Pipe-Style Interface for 'data.table'
query_if                One-to-one interface for data.table '[' method
text_expand             Evaluate expressions in curly brackets inside
                        strings
to_list                 Apply an expression to each element of a list
                        or vector
to_long                 Convert data to long or to wide form
vlookup                 Look up values in dictionary.
