Thai analyzer

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

  1. PUT /thai-index
  2. {
  3.   "mappings": {
  4.     "properties": {
  5.       "content": {
  6.         "type": "text",
  7.         "analyzer": "thai"
  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_thai_analyzer
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "analyzer": {
  6.         "stem_exclusion_thai_analyzer": {
  7.           "type": "thai",
  8.           "stem_exclusion": ["อำนาจ", "การอนุมัติ"]
  9.         }
  10.       }
  11.     }
  12.   }
  13. }

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Thai analyzer internals

The thai analyzer is built using the following components:

  • Tokenizer: thai

  • Token filters:

    • lowercase
    • decimal_digit
    • stop (Thai)
    • keyword

Custom Thai analyzer

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

  1. PUT /thai-index
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "filter": {
  6.         "thai_stop": {
  7.           "type": "stop",
  8.           "stopwords": "_thai_"
  9.         },
  10.         "thai_keywords": {
  11.           "type": "keyword_marker",
  12.           "keywords": []
  13.         }
  14.       },
  15.       "analyzer": {
  16.         "thai_analyzer": {
  17.           "tokenizer": "thai",
  18.           "filter": [
  19.             "lowercase",
  20.             "decimal_digit",
  21.             "thai_stop",
  22.             "thai_keywords"
  23.           ]
  24.         }
  25.       }
  26.     }
  27.   },
  28.   "mappings": {
  29.     "properties": {
  30.       "content": {
  31.         "type": "text",
  32.         "analyzer": "thai_analyzer"
  33.       }
  34.     }
  35.   }
  36. }

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Generated tokens

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

  1. POST /thai-index/_analyze
  2. {
  3.   "field": "content",
  4.   "text": "นักเรียนกำลังศึกษาอยู่ที่มหาวิทยาลัยไทย หมายเลข 123456."
  5. }

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The response contains the generated tokens:

  1. {
  2.   "tokens": [
  3.     {"token": "นักเรียน","start_offset": 0,"end_offset": 8,"type": "word","position": 0},
  4.     {"token": "กำลัง","start_offset": 8,"end_offset": 13,"type": "word","position": 1},
  5.     {"token": "ศึกษา","start_offset": 13,"end_offset": 18,"type": "word","position": 2},
  6.     {"token": "มหาวิทยาลัย","start_offset": 25,"end_offset": 36,"type": "word","position": 5},
  7.     {"token": "ไทย","start_offset": 36,"end_offset": 39,"type": "word","position": 6},
  8.     {"token": "หมายเลข","start_offset": 40,"end_offset": 47,"type": "word","position": 7},
  9.     {"token": "123456","start_offset": 48,"end_offset": 54,"type": "word","position": 8}
  10.   ]
  11. }