====== Blacklists and whitelists ======

==== Blacklists ====

A blacklist is a list of "bad" words (e.g., pornographic terms). If a document contains more than a certain number of [[http://en.wikipedia.org/wiki/Type-token_distinction|types]] or [[http://en.wikipedia.org/wiki/Token_(parser)#Token|tokens]] from this list, it will be discarded.

The "Types" and "Tokens" parameters let you specify the number of types and tokens from the "bad" word list sufficient to cause a document to be discarded.

==== Whitelists ====

A whitelist is a list of "good" words (e.g., function words). A document is included in the corpus only if it contains a certain number of [[http://en.wikipedia.org/wiki/Type-token_distinction|types]] and [[http://en.wikipedia.org/wiki/Token_(parser)#Token|tokens]] from this list, and if the ratio of tokens from the list to total tokens is above a certain threshold.

The "Types", "Tokens" and "Ratio" parameters let you specify the minimum number of types and tokens from the whitelist that a document must contain to be included, and the minimum ratio of tokens from the list to total tokens in the document that a document must have to be included.