Class FuzzyLikeThisQuery

Fuzzifies ALL terms provided as strings and then picks the best n differentiating terms. In effect this mixes the behaviour of FuzzyQuery and MoreLikeThis but with special consideration of fuzzy scoring factors. This generally produces good results for queries where users may provide details in a number of fields and have no knowledge of boolean query syntax and also want a degree of fuzzy matching and a fast query.

For each source term the fuzzy variants are held in a BooleanQuery with no coord factor (because we are not looking for matches on multiple variants in any one doc). Additionally, a specialized TermQuery is used for variants and does not use that variant term's IDF because this would favour rarer terms eg misspellings. Instead, all variants use the same IDF ranking (the one for the source query term) and this is factored into the variant's boost. If the source query term does not exist in the index the average IDF of the variants is used.

Inheritance

System.Object

Query

FuzzyLikeThisQuery

Inherited Members

Query.Boost

Query.ToString()

Query.CreateWeight(IndexSearcher)

Lucene.Net.Search.Query.ExtractTerms(ISet<>)

Query.Clone()

Namespace: Lucene.Net.Sandbox.Queries

Assembly: Lucene.Net.Sandbox.dll

Syntax

public class FuzzyLikeThisQuery : Query

Constructors

FuzzyLikeThisQuery(Int32, Analyzer)

Declaration

public FuzzyLikeThisQuery(int maxNumTerms, Analyzer analyzer)

Parameters

Type	Name	Description
System.Int32	maxNumTerms	The total number of terms clauses that will appear once rewritten as a BooleanQuery
Analyzer	analyzer

Properties

IgnoreTF

Declaration

public virtual bool IgnoreTF { get; set; }

Property Value

Type	Description
System.Boolean

Methods

AddTerms(String, String, Single, Int32)

Adds user input for "fuzzification"

Declaration

public virtual void AddTerms(string queryString, string fieldName, float minSimilarity, int prefixLength)

Parameters

Type	Name	Description
System.String	queryString	The string which will be parsed by the analyzer and for which fuzzy variants will be parsed
System.String	fieldName	The minimum similarity of the term variants (see FuzzyTermsEnum)
System.Single	minSimilarity	Length of required common prefix on variant terms (see FuzzyTermsEnum)
System.Int32	prefixLength

Equals(Object)

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
System.Object	obj

Returns

Type	Description
System.Boolean

GetHashCode()

Declaration

public override int GetHashCode()

Returns

Type	Description
System.Int32

Overrides

Query.GetHashCode()

Rewrite(IndexReader)

Declaration

public override Query Rewrite(IndexReader reader)

Parameters

Type	Name	Description
IndexReader	reader

Returns

Type	Description
Query

Overrides

Query.Rewrite(IndexReader)

ToString(String)

(non-Javadoc)

Declaration

public override string ToString(string field)

Parameters

Type	Name	Description
System.String	field

Returns

Type	Description
System.String