[R] Wriritng to a CSV file

[David Winsemius]

On Feb 8, 2012, at 2:29 PM, Ron Michael wrote:

> Okay, so I understood that appending can only happen row-wise.  
> Therefore I tried with following code:
>
>> write.csv(matrix(1:5, 1), "dat.csv")
>> write.csv(matrix(1:5, 1), "dat.csv", append = TRUE)
> Warning message:
> In write.csv(matrix(1:5, 1), "dat.csv", append = TRUE) :
>   attempt to set 'append' ignored
>
> It is destroying my previous file. Where I have done wrong?

Failed to read the help page. `write.csv` has some of its setting hard  
coded and will prevent you from changing them. "append" happened to be  
in that list.

Here's the code.... it's right there for all to see:

     Call <- match.call(expand.dots = TRUE)
     for (argname in c("append", "col.names", "sep", "dec",  
"qmethod")) if (!is.null(Call[[argname]]))
         warning(gettextf("attempt to set '%s' ignored", argname),
             domain = NA)
-- 

David.
>
> Thanks,
>
>
> ----- Original Message -----
> From: Uwe Ligges <ligges at statistik.tu-dortmund.de>
> To: Ron Michael <ron_michael70 at yahoo.com>
> Cc: "r-help at r-project.org" <r-help at r-project.org>
> Sent: Thursday, 9 February 2012 1:07 AM
> Subject: Re: [R] Wriritng to a CSV file
>
>
>
> On 08.02.2012 20:14, Ron Michael wrote:
>> Dear all, let say I want to write a vector to a CSV file. So I can  
>> have following syntax:
>>
>> write.csv(rnorm(10), "dat.csv")
>>
>> Now I want to add one more column into that existing file. If I use  
>> the same code then existing file will be destroyed. Is there any  
>> functionality to add without destroying the existing file? I have  
>> tries with 'append = TRUE' however it is not working!
>>
>> Any suggestion will be highly appreciated.
>
> Since these text files are written line by line, you cannot add a  
> column
> afterwards, you can just append rows.
>
> Hence read the first column and write a two column data.frame  
> afterwards.
>
> Uwe Ligges
>
>
>> ______________________________________________
>> 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.

David Winsemius, MD
West Hartford, CT