Question

我正在运行mapreduce作业，但始终无法显示缺少的输入。不幸的是，它没有显示出缺少的地方

from mrjob.job import MRJob
from mrjob.step import MRStep
import re

class flight_combination(MRJob):
    def steps(self):
        return [MRStep(mapper=self.mapper_1,reducer=self.reducer_1)]

    def mapper_1(self,_,value):
        group1 = {}
        group2 = {}
        parts = value.split(",")
        destination = parts[0]
        origin = parts[1]
        count = parts[2]
        group1[destination] = {'Origin': origin, 'count': count}
        group2[origin] = {'Destination':destination,'count':count}
        yield group1
        yield group2

    def reducer_1(self,key,value):
        g1,g2 = data
        for key1 in g1:
            for key2 in g2:
                if g1[key1]['Origin'] == g2[key2]['Destination']:
                    total = int(g1[key1]['count'])*int(g2[key2]['count'])
                yield (key1,key2,total)

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

以下是错误：

`File "wd.py", line 35, in <module>
   flight_combination.run()
…...
  File "/usr/lib/python3.6/site-packages/mrjob/job.py", line 536, in run_mapper
    for out_key, out_value in mapper(key, value) or ():
ValueError: not enough values to unpack (expected 2, got 1)`

Answer 1

对象类型run的{{1}}方法期望2个参数，但提供1个参数。（默认情况下，Python将flight_combination作为对象上调用的方法的第一个参数）

要解决此问题-

由于方法self是在父类中定义的，因此请仔细检查其定义并传递另一个参数。
通过重新定义run类来覆盖run方法，并提供您的逻辑。

我收到错误消息：ValueError：没有足够的值要解包（预期2，得到1）。可能是什么问题呢？

1 个答案: