Class PhraseQuery

A Query that matches documents containing a particular sequence of terms. A PhraseQuery is built by QueryParser for input like "new york".

This query may be combined with other terms or queries with a BooleanQuery.

Collection initializer note: To create and populate a PhraseQuery in a single statement, you can use the following example as a guide: 
var phraseQuery = new PhraseQuery() {
    new Term("field", "microsoft"), 
    new Term("field", "office")
};

Note that as long as you specify all of the parameters, you can use either Add(Term) or Add(Term, int) as the method to use to initialize. If there are multiple parameters, each parameter set must be surrounded by curly braces.

Inheritance
object
Query
PhraseQuery
NGramPhraseQuery
Inherited Members
Namespace: Lucene.Net.Search
Assembly: Lucene.Net.dll
Syntax
public class PhraseQuery : Query, IEnumerable<Term>, IEnumerable

Constructors

PhraseQuery()

Constructs an empty phrase query.

Declaration
public PhraseQuery()

Properties

Slop

Sets the number of other words permitted between words in query phrase. If zero, then this is an exact phrase search. For larger values this works like a WITHIN or NEAR operator.

The slop is in fact an edit-distance, where the units correspond to moves of terms in the query phrase out of position. For example, to switch the order of two words requires two moves (the first move places the words atop one another), so to permit re-orderings of phrases, the slop must be at least two.

More exact matches are scored higher than sloppier matches, thus search results are sorted by exactness.

The slop is zero by default, requiring exact matches.
Declaration
public virtual int Slop { get; set; }
Property Value
Type Description
int

Methods

Add(Term)

Adds a term to the end of the query phrase. The relative position of the term is the one immediately after the last term added.

Declaration
public virtual void Add(Term term)
Parameters
Type Name Description
Term term

Add(Term, int)

Adds a term to the end of the query phrase. The relative position of the term within the phrase is specified explicitly. this allows e.g. phrases with more than one term at the same position or phrases with gaps (e.g. in connection with stopwords).

Declaration
public virtual void Add(Term term, int position)
Parameters
Type Name Description
Term term
int position

CreateWeight(IndexSearcher)

Expert: Constructs an appropriate Weight implementation for this query.

Only implemented by primitive queries, which re-write to themselves.
Declaration
public override Weight CreateWeight(IndexSearcher searcher)
Parameters
Type Name Description
IndexSearcher searcher
Returns
Type Description
Weight
Overrides

Equals(object)

Returns true if o is equal to this.

Declaration
public override bool Equals(object o)
Parameters
Type Name Description
object o
Returns
Type Description
bool
Overrides

ExtractTerms(ISet<Term>)

A Query that matches documents containing a particular sequence of terms. A PhraseQuery is built by QueryParser for input like "new york".

This query may be combined with other terms or queries with a BooleanQuery.

Collection initializer note: To create and populate a PhraseQuery in a single statement, you can use the following example as a guide: 
var phraseQuery = new PhraseQuery() {
    new Term("field", "microsoft"), 
    new Term("field", "office")
};

Note that as long as you specify all of the parameters, you can use either Add(Term) or Add(Term, int) as the method to use to initialize. If there are multiple parameters, each parameter set must be surrounded by curly braces.

Declaration
public override void ExtractTerms(ISet<Term> queryTerms)
Parameters
Type Name Description
ISet<Term> queryTerms
Overrides
See Also

GetEnumerator()

Returns an enumerator that iterates through the terms collection.

Declaration
public IEnumerator<Term> GetEnumerator()
Returns
Type Description
IEnumerator<Term>

An enumerator that can be used to iterate through the terms collection.

GetHashCode()

Returns a hash code value for this object.

Declaration
public override int GetHashCode()
Returns
Type Description
int
Overrides

GetPositions()

Returns the relative positions of terms in this phrase.

Declaration
public virtual int[] GetPositions()
Returns
Type Description
int[]

GetTerms()

Returns the set of terms in this phrase.

Declaration
public virtual Term[] GetTerms()
Returns
Type Description
Term[]

Rewrite(IndexReader)

Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

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

ToString(string)

Prints a user-readable version of this query.

Declaration
public override string ToString(string f)
Parameters
Type Name Description
string f
Returns
Type Description
string
Overrides

Implements