Dutch analyzer

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

  1. PUT /dutch-index
  2. {
  3.   "mappings": {
  4.     "properties": {
  5.       "content": {
  6.         "type": "text",
  7.         "analyzer": "dutch"
  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_dutch_analyzer
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "analyzer": {
  6.         "stem_exclusion_dutch_analyzer": {
  7.           "type": "dutch",
  8.           "stem_exclusion": ["autoriteit", "goedkeuring"]
  9.         }
  10.       }
  11.     }
  12.   }
  13. }

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Dutch analyzer internals

The dutch analyzer is built using the following components:

  • Tokenizer: standard

  • Token filters:

    • lowercase
    • stop (Dutch)
    • keyword
    • stemmer_override
    • stemmer (Dutch)

Custom Dutch analyzer

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

  1. PUT /dutch-index
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "filter": {
  6.         "dutch_stop": {
  7.           "type": "stop",
  8.           "stopwords": "_dutch_"
  9.         },
  10.         "dutch_stemmer": {
  11.           "type": "stemmer",
  12.           "language": "dutch"
  13.         },
  14.         "dutch_keywords": {
  15.           "type": "keyword_marker",
  16.           "keywords": []
  17.         },
  18.         "dutch_override": {
  19.           "type": "stemmer_override",
  20.           "rules": [
  21.             "fiets=>fiets",
  22.             "bromfiets=>bromfiets",
  23.             "ei=>eier",
  24.             "kind=>kinder"
  25.           ]
  26.         }
  27.       },
  28.       "analyzer": {
  29.         "dutch_analyzer": {
  30.           "type": "custom",
  31.           "tokenizer": "standard",
  32.           "filter": [
  33.             "lowercase",
  34.             "dutch_stop",
  35.             "dutch_keywords",
  36.             "dutch_override",
  37.             "dutch_stemmer"
  38.           ]
  39.         }
  40.       }
  41.     }
  42.   },
  43.   "mappings": {
  44.     "properties": {
  45.       "content": {
  46.         "type": "text",
  47.         "analyzer": "dutch_analyzer"
  48.       }
  49.     }
  50.   }
  51. }

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Generated tokens

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

  1. POST /dutch-index/_analyze
  2. {
  3.   "field": "content",
  4.   "text": "De studenten studeren in Nederland en bezoeken Amsterdam. Hun nummers zijn 123456."
  5. }

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The response contains the generated tokens:

  1. {
  2.   "tokens": [
  3.     {"token": "student","start_offset": 3,"end_offset": 12,"type": "<ALPHANUM>","position": 1},
  4.     {"token": "studer","start_offset": 13,"end_offset": 21,"type": "<ALPHANUM>","position": 2},
  5.     {"token": "nederland","start_offset": 25,"end_offset": 34,"type": "<ALPHANUM>","position": 4},
  6.     {"token": "bezoek","start_offset": 38,"end_offset": 46,"type": "<ALPHANUM>","position": 6},
  7.     {"token": "amsterdam","start_offset": 47,"end_offset": 56,"type": "<ALPHANUM>","position": 7},
  8.     {"token": "nummer","start_offset": 62,"end_offset": 69,"type": "<ALPHANUM>","position": 9},
  9.     {"token": "123456","start_offset": 75,"end_offset": 81,"type": "<NUM>","position": 11}
  10.   ]
  11. }