Remove duplicates token filteredit
Removes duplicate tokens in the same position.
The remove_duplicates filter uses Lucene’s
RemoveDuplicatesTokenFilter.
Exampleedit
To see how the remove_duplicates filter works, you first need to produce a
token stream containing duplicate tokens in the same position.
The following analyze API request uses the
keyword_repeat and
stemmer filters to create stemmed and
unstemmed tokens for jumping dog.
GET _analyze
{
"tokenizer": "whitespace",
"filter": [
"keyword_repeat",
"stemmer"
],
"text": "jumping dog"
}
The API returns the following response. Note that the dog token in position
1 is duplicated.
{
"tokens": [
{
"token": "jumping",
"start_offset": 0,
"end_offset": 7,
"type": "word",
"position": 0
},
{
"token": "jump",
"start_offset": 0,
"end_offset": 7,
"type": "word",
"position": 0
},
{
"token": "dog",
"start_offset": 8,
"end_offset": 11,
"type": "word",
"position": 1
},
{
"token": "dog",
"start_offset": 8,
"end_offset": 11,
"type": "word",
"position": 1
}
]
}
To remove one of the duplicate dog tokens, add the remove_duplicates filter
to the previous analyze API request.
GET _analyze
{
"tokenizer": "whitespace",
"filter": [
"keyword_repeat",
"stemmer",
"remove_duplicates"
],
"text": "jumping dog"
}
The API returns the following response. There is now only one dog token in
position 1.
{
"tokens": [
{
"token": "jumping",
"start_offset": 0,
"end_offset": 7,
"type": "word",
"position": 0
},
{
"token": "jump",
"start_offset": 0,
"end_offset": 7,
"type": "word",
"position": 0
},
{
"token": "dog",
"start_offset": 8,
"end_offset": 11,
"type": "word",
"position": 1
}
]
}
Add to an analyzeredit
The following create index API request uses the
remove_duplicates filter to configure a new custom
analyzer.
This custom analyzer uses the keyword_repeat and stemmer filters to create a
stemmed and unstemmed version of each token in a stream. The remove_duplicates
filter then removes any duplicate tokens in the same position.
PUT my_index
{
"settings": {
"analysis": {
"analyzer": {
"my_custom_analyzer": {
"tokenizer": "standard",
"filter": [
"keyword_repeat",
"stemmer",
"remove_duplicates"
]
}
}
}
}
}