[R] Process multiple columns of data.frame

[Thompson, David (MNR)]

I did specify only the three columns of interest
c('bd.n','ht.n','dbh.n')
as the second (column) index, and I did superficially check the results
which turned out as I had hoped. Only the three columns listed were
changed and existing values _in_ those columns were retained.
So, I appear to be on my way again.

Thanx again, DaveT.
*************************************
>-----Original Message-----
>From: jim holtman [mailto:jholtman at gmail.com] 
>Sent: November 20, 2007 04:21 PM
>To: Thompson, David (MNR)
>Cc: r-help at r-project.org
>Subject: Re: [R] Process multiple columns of data.frame
>
>The problem with that solution is that if any of the columns in a row
>has an NA in it, then all the columns of that row will be set to zero.
> Is the what you want, or do you only want the specific entries set to
>0?
>
>On Nov 20, 2007 4:07 PM, Thompson, David (MNR)
><David.John.Thompson at ontario.ca> wrote:
>> Jim,
>>
>> What I'm getting at is my lack of understanding when manipulating
>> data frame indices. I have tried something like your matrix example
>> with variants of: Bout[ 
>is.na(Bout[,c('bd.n','ht.n','dbh.n')]), ] <- 0
>>
>> only to receive the following error message:
>> Error in `[<-.data.frame`(`*tmp*`, is.na(Bout[, c("bd.n", "ht.n",
>> "dbh.n")]),  :
>>        non-existent rows not allowed
>>
>> My questions were not focussed on the assignment value but,
>> on the selection of multiple columns (of a single type) to process.
>> Which is what I meant by concisely.
>>
>> And, lo and behold, in my attempts to reframe my questions I 
>(finally)
>> came upon a solution:
>> Bout[is.na(Bout$bd.n) | is.na(Bout$ht.n) | is.na(Bout$dbh.n),
>> c('bd.n','ht.n','dbh.n')] <- 0
>>
>> Thank you for your time, DaveT.
>> *************************************
>>
>> >-----Original Message-----
>> >From: jim holtman [mailto:jholtman at gmail.com]
>> >Sent: November 20, 2007 02:25 PM
>> >To: Thompson, David (MNR)
>> >Cc: r-help at r-project.org
>> >Subject: Re: [R] Process multiple columns of data.frame
>> >
>> >It really depends on what you want to set the values that 
>contain NAs
>> >to for the various type of the columns.  Do you always want numerics
>> >=0, characters ="", and factors =whatever?  Do you want to 
>do this for
>> >all the columns in a dataframe?  If you want to it for all 
>the columns
>> >in a matrix, it is easy, since all are the same type, and you are
>> >setting them to zero (e.g., yourMatrix[is.na(yourMatrix)] <- 0).
>> >
>> >You can always write a function that can take in the names of the
>> >columns and then depending on their types set the corresponding
>> >values.  So it depends on what you mean by "concisely" and how often
>> >you want to do it.
>> >
>> >On Nov 20, 2007 12:27 PM, Thompson, David (MNR)
>> ><David.John.Thompson at ontario.ca> wrote:
>> >> Hello,
>> >>
>> >> How do I do the following more concisely?
>> >>        Bout[is.na(Bout$bd.n), 'bd.n'] <- 0
>> >>        Bout[is.na(Bout$ht.n), 'ht.n'] <- 0
>> >>        Bout[is.na(Bout$dbh.n), 'dbh.n'] <- 0
>> >>
>> >> Would the form of such a command be different
>> >> between numeric, character and factor columns?
>> >>
>> >> . . . between data.frames and matrices?
>> >>
>> >> Thanx, DaveT.
>> >> *************************************
>> >> Silviculture Data Analyst
>> >> Ontario Forest Research Institute
>> >> Ontario Ministry of Natural Resources
>> >> david.john.thompson at ontario.ca
>> >> http://ofri.mnr.gov.on.ca
>> >>
>> >> ______________________________________________
>> >> 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 you are trying to solve?
>> >
>>
>
>
>
>-- 
>Jim Holtman
>Cincinnati, OH
>+1 513 646 9390
>
>What is the problem you are trying to solve?
>