Re: request a new feature in fuzzystrmatch - Mailing list pgsql-hackers

From Liming Hu
Subject Re: request a new feature in fuzzystrmatch
Date
Msg-id 51964B61.6000408@gmail.com
Whole thread Raw
In response to Re: request a new feature in fuzzystrmatch  (Liming Hu <dawninghu@gmail.com>)
Responses Re: request a new feature in fuzzystrmatch  (Alvaro Herrera <alvherre@2ndquadrant.com>)
List pgsql-hackers
Hi Atri,

I also talked to the author of fuzzystrmatch, he also thinks it is a 
good feature.
Thanks,

Liming

On 5/17/2013 8:21 AM, Liming Hu wrote:
> Hi Atri,
>
> Thanks for the quick response.
>
> levenshtein edit distance defines operations of: insertion, deletion, 
> modification.
> Levenshtein-Damerau edit distance defines operations of: insertion, 
> deletion, modification
> and transposition (
> it will be two operations in levenshtein edit distance:
> one deletion, and one insertion,
> ).
>
> In spelling checker/corrector, i.e.
>  levenshtein('cta', 'cat') will return 2.
> but Levenshtein-Damerau('cta', 'cat') will return 1.
> if the maximum error is 1, we can not get 'cat'.
>
> In practice, Levenshtein-Damerau is more widely used than Levenshtein.
> I believe you notice "Google automated search suggestions", they use 
> Levenshtein-Damerau.
>
> Thanks,
>
> Liming
>
>
> On 5/17/2013 3:00 AM, Atri Sharma wrote:
>>
>> Sent from my iPad
>>
>> On 17-May-2013, at 6:11, Liming Hu <dawninghu@gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I am studying your levenshtein edit distance contribution in 
>>> Postgresql.
>>>
>>> Can we add Levenshtein-Damerau edit distance since it is used in
>>> spelling checker
>>> instead of levenshtein edit distance?
>>>
>>> Levenshtein-Damerau edit distance C source code:
>>>
http://stackoverflow.com/questions/10727174/dameraulevenshtein-distance-edit-distance-with-transposition-c-implementation.

>>>
>>>
>>>
>>>
>>>
>> Could you give some use cases for the same, where the proposed 
>> feature does better than the current functionalities?
>>
>> Regards,
>>
>> Atri
>




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