java - Elastic search sort field containing special characters numbers and alpahbets -

i created case insensitive analyzer

put /dhruv3 {   "settings": {     "index": {       "analysis": {         "analyzer": {           "analyzer_keyword": {             "tokenizer": "keyword",             "filter": [ "lowercase", "asciifolding" ]           }         }       }     }   },   "mappings": {     "test": {       "properties": {         "about": {           "type": "string",           "analyzer": "analyzer_keyword"         },         "firsname": {           "type": "string"         }       }     }   } } 

and used in mapping. field supposed contain aplha numerc , special characters.then inserted values about field as

1234, `pal, pal, ~pal

. besides searching need result sorted. searching working when try sort them as

get dhruv/test/_search {   "sort": [     {       "about": {         "order": "asc"       }     }   ] } 

i results in field

1234,`pal,pal,~pal

. expect them first special characters, numbers , alphabets.

i did home work , came know because of ascii values. searched internet , tried asciifolding. didn't work out. know there solution can't figure out. please guide me

you're right in sorting behavior seeing due ascii value of special characters bigger ascii value of digits. precise, looking @ ascii table, have following values:

• 1 has ascii value 49
• ` has ascii value 96
• p has ascii value 112
• ~ has ascii value 126

the asciifolding token filter transforms characters , digits not in ascii table (i.e. first 127 characters) ascii equivalent, if such 1 exists (e.g. é, è, ë, ê transformed e). since characters above in ascii table, not you're looking for.

if want special characters come first in search there several ways.

one way achieve negate ascii value come before ascii 0 character , use script sorting:

{   "sort": [     {       "_script": {         "script": "return doc['about'].value.chars[0].isletterordigit() ? 1 : -1",         "type": "number",         "order": "asc"       }     }   ] }