[R] Fast way to finding index in Vector

[Gundala Viswanath]

Yes Jim, exactly.

BTW, I found from ?match

" Matching for lists is potentially very slow and best avoided
     except in simple cases."

Since I am doing this for million of tags. Is there a faster alternatives?


- Gundala Viswanath
Jakarta - Indonesia



On Tue, Jan 13, 2009 at 12:14 PM, jim holtman <jholtman at gmail.com> wrote:
> Is this what you want:
>
>> repo <- c("AAA", "AAT", "AAC", "AAG", "ATA","ATT")
>> qr <- c("AAC", "ATT", "ATT","AAC", "ATT", "ATT", "AAT", "ATT", "ATT")
>> match(qr, repo)
> [1] 3 6 6 3 6 6 2 6 6
>>
>
>
>
> On Mon, Jan 12, 2009 at 9:22 PM, Gundala Viswanath <gundalav at gmail.com> wrote:
>> Hi Jorge and all,
>>
>> How can I modified your code when
>>
>> query size can be bigger than repository,
>> meaning that it can contain repeats.
>>
>> e.g. qr <- c("AAC", "ATT", "ATT","AAC", "ATT", "ATT", "AAT", "ATT", "ATT",  )
>>
>>
>> Sorry, I should have mentioned this earlier.
>>
>>
>> - Gundala Viswanath
>> Jakarta - Indonesia
>>
>>
>>
>> On Tue, Jan 13, 2009 at 11:11 AM, Jorge Ivan Velez
>> <jorgeivanvelez at gmail.com> wrote:
>>>
>>> Perhaps
>>> which(repo%in%qr)
>>> ?
>>> HTH,
>>>
>>> Jorge
>>>
>>>
>>> On Mon, Jan 12, 2009 at 9:07 PM, Gundala Viswanath <gundalav at gmail.com>
>>> wrote:
>>>>
>>>> Dear all,
>>>>
>>>> Suppose I have the following vector as repository:
>>>>
>>>> > repo <- c("AAA", "AAT", "AAC", "AAG", "ATA","ATT")
>>>>
>>>> Given another query vector
>>>>
>>>> > qr <- c("AAC", "ATT")
>>>>
>>>> is there a way I can find the query index in repository in a fast way.
>>>>
>>>> Giving:
>>>>
>>>> [1] 3 6
>>>>
>>>> Typically the size of  repo is around ~12million element, and
>>>> query around ~1 million element.
>>>>
>>>>
>>>> - Gundala Viswanath
>>>> Jakarta - Indonesia
>>>>
>>>> ______________________________________________
>>>> R-help at r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>>
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem that you are trying to solve?
>