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我跑在MapReduce的以下Python代码:的MapReduce:ValueError异常:值过多解压(预期2)
from mrjob.job import MRJob
import collections
bigram = collections.defaultdict(float)
unigram = collections.defaultdict(float)
class MRWordFreqCount(MRJob):
def mapper(self, _, line):
# Now we loop over lines in the system input
line = line.strip().split()
# go through each word in sentence
i = 0
for word in line:
if i > 0:
hist = word
else:
hist = ''
word = CleanWord(word) # Get the new word
# If CleanWord didn't return a string, move on
if word == None: continue
i += 1
yield word.lower(), hist.lower(), 1.0
if __name__ == '__main__':
MRWordFreqCount.run()
我得到的错误:ValueError异常:值过多解压(预期2)但我无法弄清楚为什么。有什么建议么? 我正在运行的cmd代码是: python myjob.py Test.txt --mapper
您正在从'mapper'返回3个值,而您似乎只能返回2个值。 –
谢谢。是的,你是对的 - MrJobs mapper函数只需要一个键,值作为输出。 https://pythonhosted.org/mrjob/guides/concepts.html#mapreduce-and-apache-hadoop – user1761806