combRbind: "rbind" Recombination
In datadr: Divide and Recombine for Large, Complex Data

Description Usage Arguments Details Author(s) See Also Examples

"rbind" recombination - Combine ddf divisions by row binding

1	combRbind(...)

...

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

combRbind is passed to the argument combine in recombine

Ryan Hafen

divide, recombine, combDdo, combDdf, combCollect, combMeanCoef, combMean

# Create a distributed data frame using the iris data set
bySpecies <- divide(iris, by = "Species")

# Create a function that will calculate the standard deviation of each
# variable in in a subset. The calls to 'as.data.frame()' and 't()'
# convert the vector output of 'apply()' into a data.frame with a single row
sdCol <- function(x) as.data.frame(t(apply(x, 2, sd)))

# Combine the results using rbind
combined <- recombine(addTransform(bySpecies, sdCol), combine = combRbind)
class(combined)
combined

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