combDdo: "DDO" Recombination
In datadr: Divide and Recombine for Large, Complex Data

Description Usage Arguments Details Author(s) See Also Examples

"DDO" recombination - simply collect the results into a "ddo" object

1	combDdo(...)

...

additional attributes to define the combiner (currently only used internally)

combDdo is passed to the argument combine in recombine

Ryan Hafen

divide, recombine, combCollect, combMeanCoef, combRbind, combMean

# Divide the iris data
bySpecies <- divide(iris, by = "Species")

# Add a transform that returns a list for each subset
listTrans <- function(x) {
  list(meanPetalWidth = mean(x$Petal.Width),
       maxPetalLength = max(x$Petal.Length))
}

# Apply the transform and combine using combDdo
combined <- recombine(addTransform(bySpecies, listTrans), combine = combDdo)
combined
combined[[1]]

# A more concise (and readable) way to do it
bySpecies %>%
  addTransform(listTrans) %>%
  recombine(combDdo)