Persian analyzer
The built-in persian analyzer can be applied to a text field using the following command:
PUT /persian-index
{
"mappings": {
"properties": {
"content": {
"type": "text",
"analyzer": "persian"
}
}
}
}
Stem exclusion
You can use stem_exclusion with this language analyzer using the following command:
PUT index_with_stem_exclusion_persian_analyzer
{
"settings": {
"analysis": {
"analyzer": {
"stem_exclusion_persian_analyzer": {
"type": "persian",
"stem_exclusion": ["حکومت", "تأیید"]
}
}
}
}
}
Persian analyzer internals
The persian analyzer is built using the following components:
-
Tokenizer:
standard -
Char filter:
mapping -
Token filters:
- lowercase
- decimal_digit
- normalization (Arabic)
- normalization (Persian)
- keyword
- stemmer (Norwegian)
Custom Persian analyzer
You can create a custom Persian analyzer using the following command:
PUT /persian-index
{
"settings": {
"analysis": {
"filter": {
"persian_stop": {
"type": "stop",
"stopwords": "_persian_"
},
"persian_keywords": {
"type": "keyword_marker",
"keywords": []
}
},
"char_filter": {
"null_width_replace_with_space": {
"type": "mapping",
"mappings": [ "\\u200C=>\\u0020"]
}
},
"analyzer": {
"persian_analyzer": {
"type": "custom",
"tokenizer": "standard",
"char_filter": [ "null_width_replace_with_space" ],
"filter": [
"lowercase",
"decimal_digit",
"arabic_normalization",
"persian_normalization",
"persian_stop"
]
}
}
}
},
"mappings": {
"properties": {
"content": {
"type": "text",
"analyzer": "persian_analyzer"
}
}
}
}
Generated tokens
Use the following request to examine the tokens generated using the analyzer:
POST /persian-index/_analyze
{
"field": "content",
"text": "دانشجویان در دانشگاههای ایرانی تحصیل میکنند. شمارههای آنها ۱۲۳۴۵۶ است."
}
The response contains the generated tokens:
{
"tokens": [
{"token": "دانشجويان","start_offset": 0,"end_offset": 9,"type": "<ALPHANUM>","position": 0},
{"token": "دانشگاه","start_offset": 13,"end_offset": 20,"type": "<ALPHANUM>","position": 2},
{"token": "ايراني","start_offset": 25,"end_offset": 31,"type": "<ALPHANUM>","position": 4},
{"token": "تحصيل","start_offset": 32,"end_offset": 37,"type": "<ALPHANUM>","position": 5},
{"token": "شماره","start_offset": 47,"end_offset": 52,"type": "<ALPHANUM>","position": 8},
{"token": "123456","start_offset": 63,"end_offset": 69,"type": "<NUM>","position": 12}
]
}