David Pollak wrote:
Howdy,
Can anyone point me to an example of chaining MapReduce operations
(e.g., Word Count followed by inverting the "Word" and "Count" columns
so one wound up with the list sorted by count rather than by word)?
Nutch uses this in several places, e.g.:
org.apache.nutch.crawl.Generator
org.apache.nutch.crawl.CrawlDbReader
org.apache.nutch.crawl.Injector
org.apache.nutch.indexer.DeleteDuplicates
...
You simply switch the key and value in your map() method, just remember
to set the output classes for keys and values accordingly.
--
Best regards,
Andrzej Bialecki <><
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