[R] how to do this "the R way"

onyourmark william108 at gmail.com
Sat Apr 4 10:31:27 CEST 2009


WOW. Is it really that compact? I will give it a try. Amazing if true.
Thanks.

Patrick Burns wrote:
> 
> You need a comma (,) not a dot (.) in your
> subscripting of the matrix.  If I get the question
> correctly, you want:
> 
> newTS2 <- perm[100, TS2]
> 
> 
> Patrick Burns
> patrick at burns-stat.com
> +44 (0)20 8525 0696
> http://www.burns-stat.com
> (home of "The R Inferno" and "A Guide for the Unwilling S User")
> 
> onyourmark wrote:
>> Hi. 
>>  newTS2 =(perm[100.TS2[1]]. perm[100.TS2[2]]. perm[100.TS2[3]]. ... ,
>> perm[100.TS2[2000]])
>>
>> newTS2 is supposed to be a vector of 2000 values.
>> The first value is supposed come from a particular element of the matrix
>> called 'perm'.
>>
>> I thought that 
>> perm[100.TS2[1]]
>> would be valid code in R to refer to that element.
>> It is meant to choose the element from 'perm' in the 100th row and in the
>> column indicated by
>> TS2[1]. In other words, TS2[1] is the first element in the TS2 vector. 
>>
>> For example, if the first element in the TS2 vector was 5 then I would
>> want
>> to choose the (100,5) element from perm to be the first entry in 
>> newTS2.
>>
>> Does this make sense? Thanks.
>>
>> onyourmark wrote:
>>   
>>> Hi. I am sure there is a better way in R to do this then using a loop
>>> but
>>> I
>>> am new to it and not sure what to do. I think it might be something
>>> about
>>> using a function as an argument but not sure.
>>>
>>> I have a 1 x 2000 vector TS2 which has entries from the set {x: x is in
>>> Z
>>> and 0<x<8} (where Z is the set of Integers).
>>>
>>> Then I also have a 5050 x 7 matrix called 'perm' whose entries are also
>>> from
>>> the set {x: x is in Z and 0<x<8}
>>>
>>> I want to construct the following transformation of TS2 which will still
>>> be
>>> a vector of size 1 x 2000 and which I will call 'newTS2' such that:
>>>
>>> newTS2 =(perm[100.TS2[1]]. perm[100.TS2[2]]. perm[100.TS2[3]]. ... ,
>>>     
>>
>> Perhaps you can explain what the last line is supposed to do? This is 
>> invalid R code and also not a known mathematical notation for me ....
>>
>> Uwe Ligges
>>
>>
>>   
>>> perm[100.TS2[2000]])
>>>
>>> Is there a nice way to do this without a loop?
>>>
>>> Thank  you.
>>>     
>>
>> ______________________________________________
>> 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.
> 
> 

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