Check if Given Variable Combinations in a Data Frame are Distinct
is_distinct(x, combinations)
A list with two elements: 1) rqmt_ok
which is TRUE
if
the requirement is fulfilled and FALSE
otherwise; 2)
err_message
, the body of an error message to be used by the calling
function (mentions all problematic elements)
a data.frame
a list
of character
vectors, where each
describes a variable combination in x
to be checked for being
distinct