org.apache.commons.text.similarity

Class HammingDistance

java.lang.Object

org.apache.commons.text.similarity.HammingDistance

All Implemented Interfaces:

EditDistance<Integer>, SimilarityScore<Integer>

public class HammingDistance
extends Object
implements EditDistance<Integer>

The hamming distance between two strings of equal length is the number of positions at which the corresponding symbols are different.

For further explanation about the Hamming Distance, take a look at its Wikipedia page at http://en.wikipedia.org/wiki/Hamming_distance.

Since:

1.0

Constructor Summary

Constructors

Constructor and Description
HammingDistance()

Method Summary

Modifier and Type	Method and Description
Integer	apply(CharSequence left, CharSequence right) Find the Hamming Distance between two strings with the same length.

Methods inherited from class java.lang.Object

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

Constructor Detail

HammingDistance

public HammingDistance()

Method Detail

apply

public Integer apply(CharSequence left,
                     CharSequence right)

Find the Hamming Distance between two strings with the same length.

The distance starts with zero, and for each occurrence of a different character in either String, it increments the distance by 1, and finally return its value.

Since the Hamming Distance can only be calculated between strings of equal length, input of different lengths will throw IllegalArgumentException

 distance.apply("", "")               = 0
 distance.apply("pappa", "pappa")     = 0
 distance.apply("1011101", "1011111") = 1
 distance.apply("ATCG", "ACCC")       = 2
 distance.apply("karolin", "kerstin"  = 3
 

Specified by:

apply in interface EditDistance<Integer>

Specified by:

apply in interface SimilarityScore<Integer>

Parameters:

left - the first CharSequence, must not be null

right - the second CharSequence, must not be null

Returns:

distance

Throws:

IllegalArgumentException - if either input is null or if they do not have the same length