These functions extract a designated subset of an object of class
"fv", or replace the designated subset with other data,
or delete the designated subset.
The subset is specified by the
row index i and column index j, or
by the column name name. Either i or j
may be missing, or both may be missing.
The function [.fv is a method for the generic operator
[ for the class "fv". It extracts the
designated subset of x, and returns it as
another object of class "fv" (if drop=FALSE)
or as a data frame or vector (if drop=TRUE).
The function [<-.fv is a method for the generic operator
[<- for the class "fv".
If value is NULL, the designated subset of x will be
deleted from x.
Otherwise, the designated subset of x will be
replaced by the data contained in value.
The return value is the modified object x.
The function $<-.fv is a method for the generic operator
$<- for the class "fv".
If value is NULL, the designated column of x will be
deleted from x.
Otherwise, the designated column of x will be
replaced by the data contained in value.
The return value is the modified object x.