pframe
objects) inherit from data frames.
These objects are generated by the
pframe
function.
In addition to the attributes of data frames:
The essential difference between
pframe.objects
and data frames
is that they contain special
parameters ,which are just a list of arbitrary named objects, kept separate
from the variables in the data frame specifically so they will
not be subject to the constraints that all variables apply to the
same set of observations.
When a
pframe
is attached to the search list, the constraint is dropped
and the parameters become accessible by name, just as the variables are.