a vector of old variable names
(i.e., variable names to change)
new_var_names
a vector of new variable names
skip_absent
If skip_absent = TRUE, old variable names
that do not exist in the data set will be skipped (default = TRUE).
print_summary
If print_summary = TRUE, a summary of
old and new variable names will printed. (default = TRUE)
output_type
type of the output. If output_type = "dt",
the function's output will be a data.table with changed names.
If output_type = "summary", the function's output will
be a data.table listing old and new variable names.
By default, output_type = "dt".