Finnish analyzer

The built-in finnish analyzer can be applied to a text field using the following command:

  1. PUT /finnish-index
  2. {
  3.   "mappings": {
  4.     "properties": {
  5.       "content": {
  6.         "type": "text",
  7.         "analyzer": "finnish"
  8.       }
  9.     }
  10.   }
  11. }

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Stem exclusion

You can use stem_exclusion with this language analyzer using the following command:

  1. PUT index_with_stem_exclusion_finnish_analyzer
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "analyzer": {
  6.         "stem_exclusion_finnish_analyzer": {
  7.           "type": "finnish",
  8.           "stem_exclusion": ["valta", "hyväksyntä"]
  9.         }
  10.       }
  11.     }
  12.   }
  13. }

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Finnish analyzer internals

The finnish analyzer is built using the following components:

  • Tokenizer: standard

  • Token filters:

    • lowercase
    • stop (Finnish)
    • keyword
    • stemmer (Finnish)

Custom Finnish analyzer

You can create a custom Finnish analyzer using the following command:

  1. PUT /finnish-index
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "filter": {
  6.         "finnish_stop": {
  7.           "type": "stop",
  8.           "stopwords": "_finnish_"
  9.         },
  10.         "finnish_stemmer": {
  11.           "type": "stemmer",
  12.           "language": "finnish"
  13.         },
  14.         "finnish_keywords": {
  15.           "type": "keyword_marker",
  16.           "keywords": ["Helsinki", "Suomi"]
  17.         }
  18.       },
  19.       "analyzer": {
  20.         "finnish_analyzer": {
  21.           "type": "custom",
  22.           "tokenizer": "standard",
  23.           "filter": [
  24.             "lowercase",
  25.             "finnish_stop",
  26.             "finnish_keywords",
  27.             "finnish_stemmer"
  28.           ]
  29.         }
  30.       }
  31.     }
  32.   },
  33.   "mappings": {
  34.     "properties": {
  35.       "content": {
  36.         "type": "text",
  37.         "analyzer": "finnish_analyzer"
  38.       }
  39.     }
  40.   }
  41. }

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Generated tokens

Use the following request to examine the tokens generated using the analyzer:

  1. POST /finnish-index/_analyze
  2. {
  3.   "field": "content",
  4.   "text": "Opiskelijat opiskelevat Helsingissä ja Suomen yliopistoissa. Heidän numeronsa ovat 123456."
  5. }

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The response contains the generated tokens:

  1. {
  2.   "tokens": [
  3.     {"token": "opiskelij","start_offset": 0,"end_offset": 11,"type": "<ALPHANUM>","position": 0},
  4.     {"token": "opiskelev","start_offset": 12,"end_offset": 23,"type": "<ALPHANUM>","position": 1},
  5.     {"token": "helsing","start_offset": 24,"end_offset": 35,"type": "<ALPHANUM>","position": 2},
  6.     {"token": "suome","start_offset": 39,"end_offset": 45,"type": "<ALPHANUM>","position": 4},
  7.     {"token": "yliopisto","start_offset": 46,"end_offset": 59,"type": "<ALPHANUM>","position": 5},
  8.     {"token": "numero","start_offset": 68,"end_offset": 77,"type": "<ALPHANUM>","position": 7},
  9.     {"token": "123456","start_offset": 83,"end_offset": 89,"type": "<NUM>","position": 9}
  10.   ]
  11. }