[R] Cannot read or write to file in Linux Ubuntu

[Sarah Goslee]

Hi John,

You're probably messing up the path, just as you suspect.

If you use a relative path, like you are doing, then R looks for that
location starting at R's current working directory, visible with
getwd(). For linux, that's the location at which you started R if you
started it from a terminal.

The safest solution is to use an absolute path, which will likely be
something resembling "/home/john/DATA/... etc" - note that it will
always start with a / and go from there.

If you know how to start a terminal window and cd to where your file
is, pwd at the command prompt will give you the absolute path to that
location, which is what you should be using until you get more
comfortable with the file system.

The error message means that R can't find the directory you're telling
it to use.

Sarah

On Thu, May 3, 2012 at 12:21 PM, John Kane <jrkrideau at inbox.com> wrote:
> I am the proud owner of a new laptop since my old one died the other day.
> Currently I have a dual-boot Windows 7 Home and Ubuntu 12.04 .  I'll leave the Windows problems for another post.
>
>  I know practically nothing about Linux so I am probably doing something stupid but ... at the moment I cannot seem read or write  files in Ubuntu.   I am not having any problem saving other documents to the hard drive and R , from my few simple tests, seems to be working okay otherwise.
>
> At the moment I am trying :
>
> mydata <- read.csv("DATA/media/DATA/rdata/tt1.csv",  header = TRUE)
>  or
> mydata <- read.csv("DATA/rdata/tt1.csv",  header = TRUE)
>
>
> where tt1.csv is a text file on what, from my reading of the path listed  in gedit is
> DATA/media/DATA/rdata
>
> The csv data is simply:
> aa, bb
> 2, 3
> 4, 5
>
> What happens:
> -------------------------------------------------------------------------------
> 1> mydata <- read.csv("DATA/rdata/tt1.csv",  header = TRUE)
> Error in file(file, "rt") : cannot open the connection
> In addition: Warning message:
> In file(file, "rt") :
>  cannot open file 'DATA/rdata/tt1.csv': No such file or directory
>
> Am I totally screwing up the path?  Or doing something else equally stupid?
>
> BTW I realise that 2.15 is out but Ubuntu as of yesterday did not have it in the repositories and I have yet to figure out how to install it from a CRAN site.
>
> 1> sessionInfo()
> R version 2.14.1 (2011-12-22)
> Platform: i686-pc-linux-gnu (32-bit)
>
> locale:
>  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
>  [3] LC_TIME=en_CA.UTF-8        LC_COLLATE=en_US.UTF-8
>  [5] LC_MONETARY=en_CA.UTF-8    LC_MESSAGES=en_US.UTF-8
>  [7] LC_PAPER=C                 LC_NAME=C
>  [9] LC_ADDRESS=C               LC_TELEPHONE=C
> [11] LC_MEASUREMENT=en_CA.UTF-8 LC_IDENTIFICATION=C
>
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base

-- 
Sarah Goslee
http://www.functionaldiversity.org