Ratcliff/Obershelp pattern recognition


Definition: Compute the similarity of two strings as the number of matching characters divided by the total number of characters in the two strings. Matching characters are those in the longest common substring plus, recursively, matching characters in the unmatched region on either side of the longest common substring.

Generalization (I am a kind of ...)
string matching with errors.

Author: PEB

More information

John W. Ratcliff and David E. Metzener, Pattern Matching: The Gestalt Approach, Dr. Dobb's Journal, page 46, July 1988.

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Entry modified 8 January 2021.
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Cite this as:
Paul E. Black, "Ratcliff/Obershelp pattern recognition", in Dictionary of Algorithms and Data Structures [online], Paul E. Black, ed. 8 January 2021. (accessed TODAY) Available from: