Identifies observations. Stacks values by level, supplying defaults as necessary.
# S3 method for data.frame
observations(x, ..., exclude_name = NULL)
class 'observations' arranged by groups (presented first):
number of records
number of records in group
observation identifier
factor level (or special value 'numeric' for numerics)
numeric value (or special value 1 for factors)
data.frame
passed to categoricals(), numerics()
whether to drop NA levels of name; passed to gather