7.00.02 - nGram - Aster Analytics

Teradata Aster® Analytics Foundation User GuideUpdate 2

Aster Analytics
Release Number
September 2017
Content Type
Programming Reference
User Guide
Publication ID
English (United States)
Last Update

The nGram function tokenizes (splits) an input stream of text and outputs n multigrams (called n -grams) based on the specified delimiter and reset parameters. nGram provides more flexibility than standard tokenization when performing text analysis. Many two-word phrases carry important meaning (for example, "machine learning") that unigrams (single-word tokens) do not capture. This, combined with additional analytical techniques, can be useful for performing sentiment analysis, topic identification, and document classification.

nGram considers each input row to be one document, and returns a row for each unique n-gram in each document. nGram also returns, for each document, the counts of each n-gram and the total number of n-grams.

For general information about tokenization, see http://en.wikipedia.org/wiki/Lexical_analysis#Tokenizer.