Class NGramDistance

N-Gram version of edit distance based on paper by Grzegorz Kondrak, "N-gram similarity and distance". Proceedings of the Twelfth International Conference on String Processing and Information Retrieval (SPIRE 2005), pp. 115-126, Buenos Aires, Argentina, November 2005. http://www.cs.ualberta.ca/~kondrak/papers/spire05.pdf

This implementation uses the position-based optimization to compute partial matches of n-gram sub-strings and adds a null-character prefix of size n-1 so that the first character is contained in the same number of n-grams as a middle character. Null-character prefix matches are discounted so that strings with no matching characters will return a distance of 0.

Inheritance
object
NGramDistance
Implements
Inherited Members
Namespace: Lucene.Net.Search.Spell
Assembly: Lucene.Net.Suggest.dll
Syntax
public class NGramDistance : IStringDistance

Constructors

NGramDistance()

Creates an N-Gram distance measure using n-grams of size 2.

Declaration
public NGramDistance()

NGramDistance(int)

Creates an N-Gram distance measure using n-grams of the specified size.

Declaration
public NGramDistance(int size)
Parameters
Type Name Description
int size

The size of the n-gram to be used to compute the string distance.

Methods

Equals(object)

Determines whether the specified object is equal to the current object.

Declaration
public override bool Equals(object obj)
Parameters
Type Name Description
object obj

The object to compare with the current object.
Returns
Type Description
bool

true if the specified object is equal to the current object; otherwise, false.
Overrides

GetDistance(string, string)

Returns a float between 0 and 1 based on how similar the specified strings are to one another.
Returning a value of 1 means the specified strings are identical and 0 means the string are maximally different.

Declaration
public virtual float GetDistance(string source, string target)
Parameters
Type Name Description
string source
string target
Returns
Type Description
float

a float between 0 and 1 based on how similar the specified strings are to one another.

GetHashCode()

Serves as the default hash function.

Declaration
public override int GetHashCode()
Returns
Type Description
int

A hash code for the current object.
Overrides

ToString()

Returns a string that represents the current object.

Declaration
public override string ToString()
Returns
Type Description
string

A string that represents the current object.
Overrides

Implements