org.simmetrics.metrics

Class DamerauLevenshtein

java.lang.Object

org.simmetrics.metrics.DamerauLevenshtein

All Implemented Interfaces:

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

public class DamerauLevenshtein
extends Object
implements StringMetric, StringDistance

Damerau-Levenshtein algorithm providing a similarity measure between two strings.

Insert/delete, substitute and transpose operations can be weighted. When the cost for substitution and/or transposition are zero Damerau-Levenshtein does not satisfy the coincidence property.

This class is immutable and thread-safe.

See Also:

Wikipedia - Damerau-Levenshtein distance, Levenshtein

Constructor Summary

Constructors

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

DamerauLevenshtein

public DamerauLevenshtein()

Constructs a new Damerau-Levenshtein metric.

DamerauLevenshtein

public DamerauLevenshtein(float insertDelete,
                          float substitute,
                          float transpose)

Constructs a new weighted Damerau-Levenshtein metric. When the cost for substitution and/or transposition are zero Damerau-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

transpose - positive cost of a transpose operation

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