seanpor wrote:
> fyi On my machine match runs *much* faster...
>
>
Not too surprising. sapply and other apply-methods are usually
expedient, but not efficient.
The order(X)[Y] method should be faster still, although perhaps not
measurably so, and of course it is less general.
>> 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, AustriaFax: +43-1-7989386
Mail: [EMAIL PROTECTED]
http://www.wifo.ac.at/Serguei.Kaniovski
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>>> Ingmar Visser
>>> Department of Psychology, University of Amsterdam
>>> Roetersstraat 15
>>> 1018 WB Amsterdam
>>> The Netherlands
>>> t: +31-20-5256723
>>>
>>>
>>>
>>> [[alternative HTML version deleted]]
>>>
>>>
>>>
>>>
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>>>
>> --
>>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
>> ~~ - ([EMAIL PROTECTED]) FAX: (+45)
>> 35327907
>>
>> __
>> R-help@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
~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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