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

    All Methods Instance Methods Concrete Methods
    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

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