from mrjob.job import MRJob
import re

WORD_RE = re.compile(r"[\w]+")

class MRAvgWordLen(MRJob):
  

def mapper(self, _, line):
    for word in WORD_RE.findall(line):
      yield None, len(word)
  
  #  no combiner because reduction is not
  #  both associative and commutative
 
  def reducer(self, _, lens):
    lens_list = list(lens)
    yield None, sum(lens_list)/len(lens_list)

if __name__ == '__main__':
  MRAvgWordLen.run()