ImportError: No module named step

Question

I am coding mapreducer in python with mrjob libaries. I installed mrjob package but when i from mrjob.step import MRStep it appear error :

    from mrjob.step import MRStep
ImportError: No module named step

Anyone can help me? Thanks so much

Answer 1

Hi everyone I solved the issue, here is the working code for the word count. Essentially, a simple substitution worked for me.

from mrjob.job import MRJob import re

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

class MRMostUsedWord(MRJob):

def mapper_get_words(self, _, line):
    # yield each word in the line
    for word in WORD_RE.findall(line):
        yield (word.lower(), 1)

def combiner_count_words(self, word, counts):
    # sum the words we've seen so far
    yield (word, sum(counts))

def reducer_count_words(self, word, counts):
    # send all (num_occurrences, word) pairs to the same reducer.
    # num_occurrences is so we can easily use Python's max() function.
    yield None, (sum(counts), word)

# discard the key; it is just None
def reducer_find_max_word(self, _, word_count_pairs):
    # each item of word_count_pairs is (count, word),
    # so yielding one results in key=counts, value=word
    yield max(word_count_pairs)

def steps(self):
    return [
        self.mr(mapper=self.mapper_get_words,
               combiner=self.combiner_count_words,
               reducer=self.reducer_count_words),
        self.mr(reducer=self.reducer_find_max_word)
    ]

if name == 'main': MRMostUsedWord.run()