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

[John Kane]

Thanks Sarah,

I suspected something like that but am still gropping around in Linux.  I vaguely remember how to cd to someplace.  Shades of DOS 3.2! Of was that Unixor both!

Also I think I was trying to be a bit too smart-alecky in where I was placing my data folder so I moved it to my home folder to simplify figuring out the path. Still thinking in Windows terms.

After a bit of trial and error:

jjohn at john-K53U:~$ cd /home/john/rdata
john at john-K53U:~/rdata$ dir
tti.csv
john at john-K53U:~/rdata$ pwd
/home/john/rdata

so 
mydata <- read.csv("/home/john/rdata/tti.csv", header = TRUE)
 works just fine.  I like the idea of staying with absolute paths.

I am most appreciative.

John Kane
Kingston ON Canada


> -----Original Message-----
> From: sarah.goslee at gmail.com
> Sent: Thu, 3 May 2012 12:29:14 -0400
> To: jrkrideau at inbox.com
> Subject: Re: [R] Cannot read or write to file in Linux Ubuntu
> 
> 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

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