Here is a direct link to the full code example from the article:

http://elasticmapreduce.s3.amazonaws.com/samples/similarity/...

You will get much better performance out of Hadoop if you do this in Java, but I thought python would be more readable for a wider audience. Hadoop 18.3 doesn't have numerical sort in streaming (see https://issues.apache.org/jira/browse/HADOOP-2302 ), so the code is slightly more complicated than it needs to be. Dumbo will also probably be supported in the next release, then the code example would be even simpler.