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
System.Object.Equals(System.Object, System.Object)
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
Namespace: Lucene.Net.Sandbox.Queries
Assembly: Lucene.Net.Sandbox.dll
Syntax
public class FuzzyLikeThisQuery : Query

Constructors

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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

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IgnoreTF

Declaration
public virtual bool IgnoreTF { get; set; }
Property Value
Type Description
System.Boolean

Methods

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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
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Equals(Object)

Declaration
public override bool Equals(object obj)
Parameters
Type Name Description
System.Object obj
Returns
Type Description
System.Boolean
Overrides
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GetHashCode()

Declaration
public override int GetHashCode()
Returns
Type Description
System.Int32
Overrides
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Rewrite(IndexReader)

Declaration
public override Query Rewrite(IndexReader reader)
Parameters
Type Name Description
IndexReader reader
Returns
Type Description
Query
Overrides
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ToString(String)

(non-Javadoc) ToString(String)

Declaration
public override string ToString(string field)
Parameters
Type Name Description
System.String field
Returns
Type Description
System.String
Overrides