Shingle Token Filteredit

Note

Shingles are generally used to help speed up phrase queries. Rather than building filter chains by hand, you may find it easier to use the index-phrases option on a text field.

A token filter of type shingle that constructs shingles (token n-grams) from a token stream. In other words, it creates combinations of tokens as a single token. For example, the sentence "please divide this sentence into shingles" might be tokenized into shingles "please divide", "divide this", "this sentence", "sentence into", and "into shingles".

This filter handles position increments > 1 by inserting filler tokens (tokens with termtext "_"). It does not handle a position increment of 0.

The following are settings that can be set for a shingle token filter type:

Setting Description

max_shingle_size

The maximum shingle size. Defaults to 2.

min_shingle_size

The minimum shingle size. Defaults to 2.

output_unigrams

If true the output will contain the input tokens (unigrams) as well as the shingles. Defaults to true.

output_unigrams_if_no_shingles

If output_unigrams is false the output will contain the input tokens (unigrams) if no shingles are available. Note if output_unigrams is set to true this setting has no effect. Defaults to false.

token_separator

The string to use when joining adjacent tokens to form a shingle. Defaults to " ".

filler_token

The string to use as a replacement for each position at which there is no actual token in the stream. For instance this string is used if the position increment is greater than one when a stop filter is used together with the shingle filter. Defaults to "_"

The index level setting index.max_shingle_diff controls the maximum allowed difference between max_shingle_size and min_shingle_size.