python - 从 IPython notebook 运行 MRJob

Question

我正在尝试从 IPython notebook 运行 mrjob 示例

from mrjob.job import MRJob


class MRWordFrequencyCount(MRJob):

def mapper(self, _, line):
    yield "chars", len(line)
    yield "words", len(line.split())
    yield "lines", 1

def reducer(self, key, values):
    yield key, sum(values)  

然后用代码运行它

mr_job = MRWordFrequencyCount(args=["testfile.txt"])
with mr_job.make_runner() as runner:
    runner.run()
    for line in runner.stream_output():
        key, value = mr_job.parse_output_line(line)
        print key, value

并得到错误:

TypeError: <module '__main__' (built-in)> is a built-in class

有没有办法从 IPython notebook 运行 mrjob？

Answer 1

我还没有找到“完美的方法”，但你可以做的一件事是创建一个笔记本单元格，使用 %%file 魔法，将单元格内容写入文件:

%%file wordcount.py
from mrjob.job import MRJob

class MRWordFrequencyCount(MRJob):

    def mapper(self, _, line):
        yield "chars", len(line)
        yield "words", len(line.split())
        yield "lines", 1

    def reducer(self, key, values):
        yield key, sum(values)

然后让 mrjob 在后面的单元格中运行该文件:

import wordcount
reload(wordcount)

mr_job = wordcount.MRWordFrequencyCount(args=['example.txt'])
with mr_job.make_runner() as runner:
    runner.run()
    for line in runner.stream_output():
        key, value = mr_job.parse_output_line(line)
        print key, value

请注意，我调用了我的文件 wordcount.py 并从 wordcount 模块导入了类 MRWordFrequencyCount -- 文件名和模块必须匹配。 Python 还缓存导入的模块，当您更改 wordcount.py 文件时，iPython 不会重新加载模块，而是使用旧的缓存模块。这就是我将 reload() 调用放在那里的原因。

引用:https://groups.google.com/d/msg/mrjob/CfdAgcEaC-I/8XfJPXCjTvQJ

更新(更短)
对于较短的第二个笔记本单元，您可以通过从笔记本中调用 shell 来运行 mrjob

! python mrjob.py shakespeare.txt

引用:http://jupyter.cs.brynmawr.edu/hub/dblank/public/Jupyter%20Magics.ipynb