Replaces a continuous variable x in the data frame, and
possibly another continuous variable x_ns derived from it, with new
values, for each level of a grouping factor (usually id)
new_x(data, x_values, group_by = "id", x = "age", x_ns = NULL)A data frame. Can also be an lgpfit or lgpmodel object, in which case data is extracted from it.
the values of x to set for each individual
name of the grouping variable, must be a factor
in data (or use group_by=NA to create a dummy grouping
factor which has only one value)
of the variable along which to extend,
must be a numeric in data
of a nonstationary variable derived from x,
must be a numeric in data
a data frame containing the following columns
all factors in the original data
x
x_ns (unless it is NULL)
Other data frame handling functions:
add_dis_age(),
add_factor(),
add_factor_crossing(),
adjusted_c_hat(),
split()