[R] data frame is killing me! help

[Don MacQueen]

At 4:57 AM -0700 10/23/09, bbslover wrote:
>Steve Lianoglou-6 wrote:
>>
>>  Hi,
>>
>>  On Oct 22, 2009, at 2:35 PM, bbslover wrote:
>>
>>>  Usage
>>>  data(gasoline)
>>>  Format
>>>  A data frame with 60 observations on the following 2 variables.
>>>  octane
>>>  a numeric vector. The octane number.
>>>  NIR
>>>  a matrix with 401 columns. The NIR spectrum
>>>
>>>  and I see the gasoline data to see below
>>>  NIR.1686 nm NIR.1688 nm NIR.1690 nm NIR.1692 nm NIR.1694 nm NIR.1696 
>>>  nm
>>>  NIR.1698 nm NIR.1700 nm
>>>  1 1.242645 1.250789 1.246626 1.250985 1.264189 1.244678 1.245913 
>>>  1.221135
>>>  2 1.189116 1.223242 1.253306 1.282889 1.215065 1.225211 1.227985 
>>>  1.198851
>>>  3 1.198287 1.237383 1.260979 1.276677 1.218871 1.223132 1.230321 
>>>  1.208742
>>>  4 1.201066 1.233299 1.262966 1.272709 1.211068 1.215044 1.232655 
>>>  1.206696
>>>  5 1.259616 1.273713 1.296524 1.299507 1.226448 1.230718 1.232864 
>>>  1.202926
>>>  6 1.24109 1.262138 1.288401 1.291118 1.229769 1.227615 1.22763 
>>>  1.207576
>>>  7 1.245143 1.265648 1.274731 1.292441 1.218317 1.218147 1.222273 
>>>  1.200446
>>>  8 1.222581 1.245782 1.26002 1.290305 1.221264 1.220265 1.227947 
>>>  1.188174
>>>  9 1.234969 1.251559 1.272416 1.287405 1.211995 1.213263 1.215883 
>>>  1.196102
>>>
>>>  look at this NIR.1686 nm NIR.1688 nm NIR.1690 nm NIR.1692 nm NIR.
>>>  1694 nm
>>>  NIR.1696 nm NIR.1698 nm NIR.1700 nm
>>>
>>>  how can I add letters NIR to my variable, because my 600 
>>>  independents never
>>>  have NIR as the prefix. however, it is needed to model the plsr.   for
>>>  example aa=plsr(y~NIR, data=data ,....), the prefix NIR is 
>>>  necessary, how
>  >> can I do with it?

Perhaps using paste(). Maybe something like:

    paste('NIR', 1:600,sep=''.)
or
    paste('NIR', seq(1686,1700,2),sep='.')

>  >
>>  I'm not really sue that I'm getting you, but if your problem is that 
>>  the column names of your data.frame don't match the variable names 
>>  you'd like to use in your formula, just change the colnames of your 
>>  data.frame to match your formula.
>>
>>  BTW - I have no idea where to get this gasoline data set, so I'm just 
>>  imagining:
>>
>>  eg.
>>  colnames(gasoline) <- c('put', 'the', 'variable', 'names', 'that', 
>>  'you', 'want', 'here')
>>
>>  -steve
>>
>>  --
>>  Steve Lianoglou
>>  Graduate Student: Computational Systems Biology
>>     |  Memorial Sloan-Kettering Cancer Center
>>     |  Weill Medical College of Cornell University
>>  Contact Info: http://*cbio.mskcc.org/~lianos/contact
>>
>>  ______________________________________________
>>  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.
>>
>>
>
>thanks for you. but the numbers of indenpendence are so many, it is not easy
>to identify them one by one,  is there some better way?
>
>
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-- 
---------------------------------
Don MacQueen
Lawrence Livermore National Laboratory
Livermore, CA, USA
925-423-1062
macq at llnl.gov