org.simmetrics.metrics

Class Levenshtein

java.lang.Object

org.simmetrics.metrics.Levenshtein

All Implemented Interfaces:

Distance<String>, Metric<String>, StringDistance, StringMetric

public class Levenshtein
extends Object
implements StringMetric, StringDistance

Levenshtein algorithm providing a similarity measure between two strings.

Insert/delete and substitute operations can be weighted. When the cost for substitution is zero Levenshtein does not satisfy the coincidence property.

This class is immutable and thread-safe.

See Also:

Wikipedia - Levenshtein distance, DamerauLevenshtein

Constructor Summary

Constructors

Constructor and Description
Levenshtein() Constructs a new Levenshtein metric.
Levenshtein(float insertDelete, float substitute) Constructs a new weighted Levenshtein metric.

Method Summary

Modifier and Type	Method and Description
float	compare(String a, String b) Measures the similarity between strings a and b.
float	distance(String s, String t) Measures the distance between string a and b.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Levenshtein

public Levenshtein(float insertDelete,
                   float substitute)

Constructs a new weighted Levenshtein metric. When the cost for substitution is zero Levenshtein does not satisfy the coincidence property.

Parameters:

insertDelete - positive non-zero cost of an insert or deletion operation

substitute - positive cost of a substitute operation

Levenshtein

public Levenshtein()

Constructs a new Levenshtein metric.

Method Detail

compare

public float compare(String a,
                     String b)

Description copied from interface: StringMetric

Measures the similarity between strings a and b. The measurement results in a value between 0 and 1 (inclusive). A value of zero indicates that the strings are dissimilar, a value of 1 indicates they are similar.

Specified by:

compare in interface Metric<String>

Specified by:

compare in interface StringMetric

Parameters:

a - string a to compare

b - string b to compare

Returns:

a value between 0 and 1 inclusive indicating similarity

distance

public float distance(String s,
                      String t)

Description copied from interface: StringDistance

Measures the distance between string a and b. The measurement results in a non-negative value. A value of 0.0 indicates that a and b are similar.

Specified by:

distance in interface Distance<String>

Specified by:

distance in interface StringDistance

Parameters:

s - string a to compare

t - string b to compare

Returns:

a non-negative value

toString

public String toString()

Overrides:

toString in class Object