There are several importers and exporters for common file formats.

General-purpose convertors

Importer 'bin/mahout' jobs

Run these with --help to see options

• bin/mahout arff.vector
• bin/mahout lucene.vector
• bin/mahout seqdirectory
  • turns text files into sequence files, one file per key/value pair
• bin/mahout SequenceFilesFromMailArchives
  • parses mailboxes and emits one text body per mail message
• bin/mahout regexconverter
  • reads text lines and emits the regex output lines into SequenceFiles.

Exporter 'bin/mahout' jobs

Some programs exist to dump text versions of SequenceFiles for perusal. Run these with --help to see options.

• bin/mahout clusterdump
• bin/mahout cmdump
• bin/mahout matrixdump
• bin/mahout seqdumper
• bin/mahout vectordump

Note: all classes with a 'main' method can be used as a bin/mahout job name.

Importer classes

These are not main() classes and must be coded against.

• CSVVectorIterator imports CSV files into vectors.

Exporter classes

• GraphMLClusterWriter saves cluster data in the GraphML
• CSVClusterWriter saves clusters in a csv-based format.

Both of these formats are read by the Gephi program, an interactive graph explorer.

There are many file importers which are custom-made for particular algorithms:

• The various text -> Lucene index converters

Examples

Regex Converter

For example, the following will extract queries from HTTP request logs to Solr and prepare them for use by Frequent Itemset Mining.

bin/mahout regexconverter --input /Users/grantingersoll/projects/content/lucid/lucidfind/logs --output /tmp/solr/output --regex "(?<=(\?|&)q=).*?(?=&|$)" --overwrite --transformerClass url --formatterClass fpg

See tutorial and cheat sheet for this marvelously opaque toolkit.