Truncate token filter
editTruncate token filter
editTruncates tokens that exceed a specified character limit. This limit defaults to
10
but can be customized using the length
parameter.
For example, you can use the truncate
filter to shorten all tokens to
3
characters or fewer, changing jumping fox
to jum fox
.
This filter uses Lucene’s TruncateTokenFilter.
Example
editThe following analyze API request uses the truncate
filter
to shorten tokens that exceed 10 characters in
the quinquennial extravaganza carried on
:
GET _analyze { "tokenizer" : "whitespace", "filter" : ["truncate"], "text" : "the quinquennial extravaganza carried on" }
The filter produces the following tokens:
[ the, quinquenni, extravagan, carried, on ]
Add to an analyzer
editThe following create index API request uses the
truncate
filter to configure a new
custom analyzer.
PUT custom_truncate_example { "settings" : { "analysis" : { "analyzer" : { "standard_truncate" : { "tokenizer" : "standard", "filter" : ["truncate"] } } } } }
Configurable parameters
edit-
length
-
(Optional, integer)
Character limit for each token. Tokens exceeding this limit are truncated.
Defaults to
10
.
Customize
editTo customize the truncate
filter, duplicate it to create the basis
for a new custom token filter. You can modify the filter using its configurable
parameters.
For example, the following request creates a custom truncate
filter,
5_char_trunc
, that shortens tokens to a length
of 5
or fewer characters:
PUT 5_char_words_example { "settings": { "analysis": { "analyzer": { "lowercase_5_char": { "tokenizer": "lowercase", "filter": [ "5_char_trunc" ] } }, "filter": { "5_char_trunc": { "type": "truncate", "length": 5 } } } } }