[R] Re placing values job

[seanpor]

fyi On my machine match runs *much* faster...

> t0 <- Sys.time(); for (i in 1:reps) { match(Y,X) }; print(Sys.time() - t0)
Time difference of 0.1570001 secs
> t0 <- Sys.time(); for (i in 1:reps) { sapply(Y,function(Y){which(Y==X)})
> }; print(Sys.time() - t0)
Time difference of 6.093 secs
> 6.09/.157
[1] 38.78981

Regards,
Sean


Peter Dalgaard wrote:
> 
> Ingmar Visser wrote:
>> does this do what you want?
>>
>> sapply(y,function(y){which(y==x)})
>>   
> Maybe, but match(Y,X) would be more to the point.
> 
>> hth, Ingmar
>>
>> On 28 Nov 2007, at 15:53, Serguei Kaniovski wrote:
>>
>>   
>>> Hallo,
>>>
>>> I have two vectors of different lengths which contain the same set of
>>> values:
>>>
>>> X < -c(2,6,1,7,4,3,5)
>>> Y <- c(1,1,6,4,6,1,4,1,2,3,6,6,1,2,4,4,5,4,1,7,6,6,4,4,7,1,2)
>>>
>>> How can I replace the values in Y with the index (!) of the  
>>> corresponding
>>> values in X. So 2 appears in X in the first coordinate, so all 2�s  
>>> in Y
>>> should be replaced by 1, etc.
>>>
>>> Thank you for your help,
>>> Serguei
>>>
>>> ________________________________________
>>> Austrian Institute of Economic Research (WIFO)
>>>
>>> P.O.Box 91                          Tel.: +43-1-7982601-231
>>> 1103 Vienna, Austria        Fax: +43-1-7989386
>>>
>>> Mail: Serguei.Kaniovski at wifo.ac.at
>>> http://www.wifo.ac.at/Serguei.Kaniovski
>>> 	[[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> 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.
>>>     
>>
>> Ingmar Visser
>> Department of Psychology, University of Amsterdam
>> Roetersstraat 15
>> 1018 WB Amsterdam
>> The Netherlands
>> t: +31-20-5256723
>>
>>
>>
>> 	[[alternative HTML version deleted]]
>>
>>   
>> ------------------------------------------------------------------------
>>
>> ______________________________________________
>> 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.
>>   
> 
> 
> -- 
>    O__  ---- Peter Dalgaard             Øster Farimagsgade 5, Entr.B
>   c/ /'_ --- Dept. of Biostatistics     PO Box 2099, 1014 Cph. K
>  (*) \(*) -- University of Copenhagen   Denmark          Ph:  (+45)
> 35327918
> ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)                  FAX: (+45)
> 35327907
> 
> ______________________________________________
> 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.
> 
> 

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