aggregatinFuntion2 creates statistical summaries of two numerical vectors that
are formula aware.
Usage
aggregatingFunction2(fun)
Arguments
fun
a function that takes two numeric vectors and computes a summary statistic,
returning a numeric vector of length 1.
Value
a function that generalizes fun to handle a formula/data frame interface.
Note
Earlier versions of this function supported a "bare name + data frame" interface. This
functionality has been removed since it was (a) ambiguous in some cases, (b) unnecessary,
and (c) difficult to maintain.
Details
This was designed to support functions like cov() which can be used to compute
numerical summaries from two numeric vectors.
The logic of the resulting function is this: 1) If the first two arguments are both formulas,
then those formulas are evaluated (with data) to compute the covariance;
(2) If the first argument is a formula, and the second is NULL,
then the left and ride sides of the formula and data are used to create the
vectors passed to fun;
(3) Else everything is simply passed to fun for evaluation.