[R] Wriritng to a CSV file

Ron Michael ron_michael70 at yahoo.com
Wed Feb 8 20:29:33 CET 2012

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?

----- 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

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