Example RHadoop MR Task

example.R

library(rmr2)

groups <- rbinom(32, n = 50, prob = 0.4)
print(groups)

groups.dfs <- to.dfs(groups)

from.dfs(
  mapreduce(
    input = groups.dfs, 
    map = function(., v) keyval(v, 1), 
    reduce = 
        function(k, vv) 
          keyval(k, length(vv))
    )
)