ave_dfm {quest}

Repeated Group Statistics for a Data-Frame

Description

ave_dfm evaluates a function on a set of variables vrb.nm separately for each group within grp.nm. The results are combined back together in line with the rows of data similar to ave. ave_dfm is different than ave or agg because it operates on a data.frame, not an atomic vector.

Usage

ave_dfm(data, vrb.nm, grp.nm, fun, ...)

Arguments

data

data.frame of data.

vrb.nm

character vector of colnames in data specifying the variables to use for the aggregation function fun.

grp.nm

character vector of colnames in data specifying the grouping variables.

fun

function that returns an atomic vector of length 1. Probably makes sense to ensure the function always returns the same typeof as well.

...

additional named arguments to fun.

Value

atomic vector of length = nrow(data) providing the result of the function fun for the subset of data with that group value (i.e., data[levels(interaction(data[grp.nm]))[i], vrb.nm]) for that row.

See Also

ave for the same functionality with atomic vector inputs agg_dfm for similar functionality with data.frames, but can return the result for each group once rather than repeating the result for each group value in the data.frame

Examples

# one grouping variables
ave_dfm(data = airquality, vrb.nm = c("Ozone","Solar.R"), grp.nm = "Month",
   fun = function(dat) cor(dat, use = "complete")[1,2])

# two grouping variables
ave_dfm(data = mtcars, vrb.nm = c("mpg","cyl","disp"), grp.nm = c("vs","am"),
   fun = nrow) # with multiple group columns