Arabic analyzer

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

  1. PUT /arabic-index
  2. {
  3.   "mappings": {
  4.     "properties": {
  5.       "content": {
  6.         "type": "text",
  7.         "analyzer": "arabic"
  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_arabic
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "analyzer": {
  6.         "stem_exclusion_arabic_analyzer":{
  7.           "type":"arabic",
  8.           "stem_exclusion":["تكنولوجيا","سلطة "]
  9.         }
  10.       }
  11.     }
  12.   }
  13. }

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Arabic analyzer internals

The arabic analyzer is built using the following components:

  • Tokenizer: standard

  • Token filters:

    • lowercase
    • decimal_digit
    • stop (Arabic)
    • normalization (Arabic)
    • keyword
    • stemmer (Arabic)

Custom Arabic analyzer

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

  1. PUT /arabic-index
  2. {
  3.   "settings": {
  4.     "analysis": {
  5.       "filter": {
  6.         "arabic_stop": {
  7.           "type": "stop",
  8.           "stopwords": "_arabic_"
  9.         },
  10.         "arabic_stemmer": {
  11.           "type": "stemmer",
  12.           "language": "arabic"
  13.         },
  14.         "arabic_normalization": {
  15.           "type": "arabic_normalization"
  16.         },
  17.         "decimal_digit": {
  18.           "type": "decimal_digit"
  19.         },
  20.         "arabic_keywords": {
  21.           "type":       "keyword_marker",
  22.           "keywords":   [] 
  23.         }
  24.       },
  25.       "analyzer": {
  26.         "arabic_analyzer": {
  27.           "type": "custom",
  28.           "tokenizer": "standard",
  29.           "filter": [
  30.             "lowercase",
  31.             "arabic_normalization",
  32.             "decimal_digit",
  33.             "arabic_stop",
  34.             "arabic_keywords",
  35.             "arabic_stemmer"
  36.           ]
  37.         }
  38.       }
  39.     }
  40.   },
  41.   "mappings": {
  42.     "properties": {
  43.       "content": {
  44.         "type": "text",
  45.         "analyzer": "arabic_analyzer"
  46.       }
  47.     }
  48.   }
  49. }

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Generated tokens

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

  1. POST /arabic-index/_analyze
  2. {
  3.   "field": "content",
  4.   "text": "الطلاب يدرسون في الجامعات العربية. أرقامهم ١٢٣٤٥٦."
  5. }

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The response contains the generated tokens:

  1. {
  2.   "tokens": [
  3.     {
  4.       "token": "طلاب",
  5.       "start_offset": 0,
  6.       "end_offset": 6,
  7.       "type": "<ALPHANUM>",
  8.       "position": 0
  9.     },
  10.     {
  11.       "token": "يدرس",
  12.       "start_offset": 7,
  13.       "end_offset": 13,
  14.       "type": "<ALPHANUM>",
  15.       "position": 1
  16.     },
  17.     {
  18.       "token": "جامع",
  19.       "start_offset": 17,
  20.       "end_offset": 25,
  21.       "type": "<ALPHANUM>",
  22.       "position": 3
  23.     },
  24.     {
  25.       "token": "عرب",
  26.       "start_offset": 26,
  27.       "end_offset": 33,
  28.       "type": "<ALPHANUM>",
  29.       "position": 4
  30.     },
  31.     {
  32.       "token": "ارقامهم",
  33.       "start_offset": 35,
  34.       "end_offset": 42,
  35.       "type": "<ALPHANUM>",
  36.       "position": 5
  37.     },
  38.     {
  39.       "token": "123456",
  40.       "start_offset": 43,
  41.       "end_offset": 49,
  42.       "type": "<NUM>",
  43.       "position": 6
  44.     }
  45.   ]
  46. }