[out] = groupby (obj, groupvars, aggcalcs) ¶Find groups in table data and apply functions to variables within groups.
This works like an SQL "SELECT ... GROUP BY ..." statement.
groupvars (cellstr, numeric) is a list of the grouping variables, identified by name or index.
aggcalcs is a specification of the aggregate calculations to perform
on them, in the form {out_var, fcn, in_vars; ...}, where:
out_var (char) is the name of the output variable
fcn (function handle) is the function to apply to produce it
in_vars (cellstr) is a list of the input variables to pass to fcn
Returns a table.