group_by_x() takes an existing table and converts it into a
grouped table where operations are performed "by group". ungroup() removes grouping.
summarize() reduces multiple values down to a single value.
Note: this function uses xpose.xtras::edit_xpose_data, but is otherwise
the same as <xpose::group_by>.
group_by_x(.data, ..., .problem, .source, .where)ungroup_x(.data, ..., .problem, .source, .where)
Group data in an xpose data object
An xpose database object.
Name-value pairs of expressions. Use NULL to drop a variable.
The problem from which the data will be modified
The source of the data in the xpdb. Can either be 'data' or an output file extension e.g. 'phi'.
A vector of element names to be edited in special (e.g.
.where = c('vpc_dat', 'aggr_obs') with vpc).