FT.SPELLCHECK

Syntax
FT.SPELLCHECK index query 
  [DISTANCE distance] 
  [TERMS INCLUDE | EXCLUDE dictionary [terms [terms ...]]] 
  [DIALECT dialect]
Available in:
Redis Stack / Search 1.4.0
Time complexity:
O(1)

Perform spelling correction on a query, returning suggestions for misspelled terms

Examples

Required arguments

index

is index with the indexed terms.

query

is search query.

See Spellchecking for more details.

Optional arguments

TERMS

specifies an inclusion (INCLUDE) or exclusion (EXCLUDE) of a custom dictionary named {dict}. Refer to FT.DICTADD, FT.DICTDEL and FT.DICTDUMP about managing custom dictionaries.

DISTANCE

is maximum Levenshtein distance for spelling suggestions (default: 1, max: 4).

DIALECT {dialect_version}

selects the dialect version under which to execute the query. If not specified, the query will execute under the default dialect version set during module initial loading or via FT.CONFIG SET command.

Return

FT.SPELLCHECK returns an array reply, in which each element represents a misspelled term from the query. The misspelled terms are ordered by their order of appearance in the query. Each misspelled term, in turn, is a 3-element array consisting of the constant string TERM, the term itself and an array of suggestions for spelling corrections. Each element in the spelling corrections array consists of the score of the suggestion and the suggestion itself. The suggestions array, per misspelled term, is ordered in descending order by score. The score is calculated by dividing the number of documents in which the suggested term exists by the total number of documents in the index. Results can be normalized by dividing scores by the highest score.

Examples

Perform spelling correction on a query 
127.0.0.1:6379> FT.SPELLCHECK idx held DISTANCE 2
1) 1) "TERM"
   2) "held"
   3) 1) 1) "0.66666666666666663"
         2) "hello"
      2) 1) "0.33333333333333331"
         2) "help"

See also

FT.CONFIG SET | FT.DICTADD | FT.DICTDEL | FT.DICTDUMP

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