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我希望此地圖縮減作業(下面的代碼)能夠輸出排名前10的最受歡迎的產品。它不斷給我以下錯誤信息:MapReduce作業使用Python的MRjob產生前10個值
it = izip(iterable,count(0,-1))#decorate TypeError:izip參數#1必須支持迭代。
我在想它與nlargest函數我試圖申請。
任何指針?
謝謝!
from mrjob.job import MRJob
from mrjob.step import MRStep
from heapq import nlargest
class MostRatedProduct(MRJob):
def steps(self):
return [
MRStep(mapper = self.mapper_get_ratings,
reducer = self.reducer_count_ratings),
MRStep(reducer = self.reducer_find_top10)
]
def mapper_get_ratings(self, _, line):
(userID, itemID, rating, timestamp) = line.split(',')
yield itemID, 1
def reducer_count_ratings(self, itemID, ratingCount):
yield None, (sum(ratingCount), itemID)
def top_10(self, ratingPair):
for ratingTotal, itemID in ratingPair:
top_rated = nlargest(10, ratingTotal)
for top_rated in ratingTotal:
return (ratingTotal, itemID)
def reducer_find_top10(self, key, ratingPair):
ratingTotal, itemID = self.top_10(ratingPair)
yield ratingTotal, itemID
if __name__ == '__main__':
MostRatedProduct.run()