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From Christoph Kaser <>
Subject Re: Indexing product keys with and without spaces in them
Date Tue, 03 Jan 2012 14:01:42 GMT
Hi Ian,

thank you for your reply.

Unfortunately this will be hard, as we have no way of knowing at which 
position the user might enter spaces, so we cannot expand the product 
keys at indexing time.

The other way round (triplets without spaces or hyphens) might work, 
however we have no real way of knowing whether product keys really are 
triplets, so we also have to make doublets and quadruplets (and maybe 
even quintuplets). So for every two, three, four, five consecutive 
tokens in our index, we would have to include the concatenated version. 
If we treat the user input the same way, we should be able to find type 
identifiers regardless of their spelling.

However, this would dramatically increase the index size and lead to 
false positives for situations where other words are concatenated which 
form a different word.

Has somebody ever tried something like this? Is there a way to do this 
without increasing the index to about 15 times (1+2+3+4+5) its original 


Am 03.01.2012 11:06, schrieb Ian Lea:
> When indexing you could normalise them down to a standard format
> without spaces or hyphens, but searching is much harder if you really
> can't identify possible product ids within user queries.  Make
> triplets without spaces or hyphens?  "CRX USB-2.0 16GB" ==>
> CRXUSB2.016GB but also "some random words" ==>  somerandomwords.  The
> latter wouldn't match, the former would if it was a valid id.
> Some form of synonym analysis/injection at indexing would be better if
> you could do that: CRXUSB2.016GB ==>  "CRX USB2.0 16GB", to be indexed
> as well as the base value.
> If you can't either have a dedicated product id search field or
> standardise the product ids, this is going to be hard.
> --
> Ian,
> On Tue, Jan 3, 2012 at 8:44 AM, Christoph Kaser<>  wrote:
>> Hello,
>> we use lucene as search engine in an online shop. The products in this shop
>> often contain product keys like CRXUSB2.0-16GB.
>> We would like our customers to be able to find products by entering their
>> key. The problem is that product keys sometimes contain spaces or dashes and
>> customers sometimes don't enter these whitespaces correctly. On the other
>> hand, some customers enter whitespaces where there are none. Is there an
>> analyzer or some other method that allows us to find the product if the user
>> enters things like:
>> - "CRX USB2.0 16GB"
>> - "CRXUSB2.016GB"
>> - "CRX USB-2.0 16GB"
>> ...
>> The problem is that the product keys don't all have a common format and are
>> contained in the normal text, so we don't have an easy way to treat them
>> different to the rest of the text.
>> Any help would be great!
>> Best regards,
>> Christoph
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Dipl.-Inf. Christoph Kaser

IconParc GmbH
Sophienstrasse 1
80333 München

Tel +49 -89- 15 90 06 - 21
Fax +49 -89- 15 90 06 - 49

Geschäftsleitung: Dipl.-Ing. Roland Brückner, Dipl.-Inf. Sven Angerer. HRB
121830, Amtsgericht München

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