R help - Feb 2010 - scan and skip - without line breaks in the input file

Dear all,

I am trying to read in big amounts of data with scan. It's only one
variable, numeric values, separated by tabs,.. and it's many of them. So I
was thinking that I could use the skip option and read in 100000 values at a
time - but skip doesn't work, probably because I don't have line breaks
in the txt file. So any value specified for skip makes the scan function jump to
the end of the file.

Does anyone have a good idea? I would be extremely grateful.

Kind regards,

Susanne Balzer



****************************
Susanne Balzer
PhD Student
Institute of Marine Research
N-5073 Bergen, Norway
Phone: +47 55 23 69 45
susanne.balzer at imr.no
www.imr.no

On Feb 27, 2010, at 11:24 AM, Balzer Susanne wrote:
> Dear all,
>
> I am trying to read in big amounts of data with scan. It's only one  
> variable, numeric values, separated by tabs,.. and it's many of  
> them. So I was thinking that I could use the skip option and read in  
> 100000 values at a time - but skip doesn't work, probably because I  
> don't have line breaks in the txt file. So any value specified for  
> skip makes the scan function jump to the end of the file.
?scan

Without a working example it is hard to be sure, but it appears from a  
rapid look at the help page that nmax is the argument you want.

 > scan(textConnection('1 2 3 4 5 6 7'), nmax=4)
Read 4 items
[1] 1 2 3 4


(Ignores line-feeds)
 > scan(textConnection('1 2 \n 3 4 5 6 7'), nmax=4)
Read 4 items
[1] 1 2 3 4


-- 
David.
>
> Does anyone have a good idea? I would be extremely grateful.
>
> Kind regards,
>
> Susanne Balzer
>
>
>
> ****************************
> Susanne Balzer
> PhD Student
> Institute of Marine Research
> N-5073 Bergen, Norway
> Phone: +47 55 23 69 45
> susanne.balzer at imr.no
> www.imr.no
>
> ______________________________________________
> 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
Heritage Laboratories
West Hartford, CT

On UNIX/Linux:

	myData <- scan(pipe("tr '\\t' '\\n' < myfile"),
skip = 3)

You might have to adjust this depending on your shell.  On Windows
there is a tr in Duncan Murdoch's Rtools.



On Sat, Feb 27, 2010 at 11:24 AM, Balzer Susanne <susanne.balzer at
imr.no> wrote:
> Dear all,
>
> I am trying to read in big amounts of data with scan. It's only one
variable, numeric values, separated by tabs,.. and it's many of them. So I
was thinking that I could use the skip option and read in 100000 values at a
time - but skip doesn't work, probably because I don't have line breaks
in the txt file. So any value specified for skip makes the scan function jump to
the end of the file.
>
> Does anyone have a good idea? I would be extremely grateful.
>
> Kind regards,
>
> Susanne Balzer
>
>
>
> ****************************
> Susanne Balzer
> PhD Student
> Institute of Marine Research
> N-5073 Bergen, Norway
> Phone: +47 55 23 69 45
> susanne.balzer at imr.no
> www.imr.no