mrjob v0.4.2 documentation ← Why mrjob? Concepts → Home Guides ¶ ¶ Install with pip : pip install mrjob or from a git clone of the source code : python setup.py test && python setup.py install ¶ Open a file called word_count.py and type this into it: 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 ) if __name__ == '__main__' : MRWordFrequencyCount . run () Now go back to the command line, find your favorite body of text (such mrjob’s README.rst , or even your new file word_count.py ), and try this: $ python word_count.py my_file.txt You should see something like this: "chars" 3654 "lines" 123 "words" 417 Congratulations!...