Class SlowFuzzyQuery

Implements the classic fuzzy search query. The similarity measurement is based on the Levenshtein (edit distance) algorithm.

Note that, unlike FuzzyQuery, this query will silently allow for a (possibly huge) number of edit distances in comparisons, and may be extremely slow (comparing every term in the index).

Inheritance
System.Object
Query
MultiTermQuery
SlowFuzzyQuery
Inherited Members
Lucene.Net.Search.Query.ExtractTerms(ISet<>)
Namespace: Lucene.Net.Sandbox.Queries
Assembly: Lucene.Net.Sandbox.dll
Syntax
public class SlowFuzzyQuery : MultiTermQuery

Constructors

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SlowFuzzyQuery(Term)

Calls SlowFuzzyQuery(Term, Single).

Declaration
public SlowFuzzyQuery(Term term)
Parameters
Type Name Description
Term term
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SlowFuzzyQuery(Term, Single)

Calls SlowFuzzyQuery(Term, Single).

Declaration
public SlowFuzzyQuery(Term term, float minimumSimilarity)
Parameters
Type Name Description
Term term
System.Single minimumSimilarity
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SlowFuzzyQuery(Term, Single, Int32)

Calls SlowFuzzyQuery(Term, Single).

Declaration
public SlowFuzzyQuery(Term term, float minimumSimilarity, int prefixLength)
Parameters
Type Name Description
Term term
System.Single minimumSimilarity
System.Int32 prefixLength
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SlowFuzzyQuery(Term, Single, Int32, Int32)

Create a new SlowFuzzyQuery that will match terms with a similarity of at least minimumSimilarity to term. If a prefixLength > 0 is specified, a common prefix of that length is also required.

Declaration
public SlowFuzzyQuery(Term term, float minimumSimilarity, int prefixLength, int maxExpansions)
Parameters
Type Name Description
Term term

the term to search for
System.Single minimumSimilarity

a value between 0 and 1 to set the required similarity between the query term and the matching terms. For example, for a minimumSimilarity of 0.5 a term of the same length as the query term is considered similar to the query term if the edit distance between both terms is less than length(term)*0.5

Alternatively, if minimumSimilarity is >= 1f, it is interpreted as a pure Levenshtein edit distance. For example, a value of 2f will match all terms within an edit distance of 2 from the query term. Edit distances specified in this way may not be fractional.
System.Int32 prefixLength

length of common (non-fuzzy) prefix
System.Int32 maxExpansions

the maximum number of terms to match. If this number is greater than MaxClauseCount when the query is rewritten, then the maxClauseCount will be used instead.

Fields

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defaultMaxExpansions

Declaration
public static readonly int defaultMaxExpansions
Field Value
Type Description
System.Int32
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defaultMinSimilarity

Declaration
public static readonly float defaultMinSimilarity
Field Value
Type Description
System.Single
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defaultPrefixLength

Declaration
public static readonly int defaultPrefixLength
Field Value
Type Description
System.Int32
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m_term

Declaration
protected Term m_term
Field Value
Type Description
Term

Properties

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MinSimilarity

Gets the minimum similarity that is required for this query to match. Returns float value between 0.0 and 1.0.

Declaration
public virtual float MinSimilarity { get; }
Property Value
Type Description
System.Single
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PrefixLength

Gets the non-fuzzy prefix length. This is the number of characters at the start of a term that must be identical (not fuzzy) to the query term if the query is to match that term.

Declaration
public virtual int PrefixLength { get; }
Property Value
Type Description
System.Int32
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Term

Gets the pattern term.

Declaration
public virtual Term Term { get; }
Property Value
Type Description
Term

Methods

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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
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GetHashCode()

Declaration
public override int GetHashCode()
Returns
Type Description
System.Int32
Overrides
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GetTermsEnum(Terms, AttributeSource)

Declaration
protected override TermsEnum GetTermsEnum(Terms terms, AttributeSource atts)
Parameters
Type Name Description
Terms terms
AttributeSource atts
Returns
Type Description
TermsEnum
Overrides
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ToString(String)

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