The easiest way to create a grouped data frame is to call the group_by
method on a data frame or tbl: this will take care of capturing
the unevalated expressions for you.
Usage
grouped_df(data, vars, drop = TRUE)
is.grouped_df(x)
Arguments
data
a tbl or data frame.
vars
a list of quoted variables.
drop
if TRUE preserve all factor levels, even those without
data.