[R] scan and skip - without line breaks in the input file

[Balzer Susanne]

Hei David,

Thanks for your quick response, but unfortunately n and nmax alone don't do the job. If I want to read items no. 100001 to 200000, the n=100000 option will work, but skip=100000 (to NOT read the first 100000 items) won't.

Or with your example,

scan(textConnection('1 2 3 4 5 6 7'), skip=3) will never work, while

scan(textConnection('1 2 3 4 \n 5 \n 6 \n 7'), skip=3) will. But I don't have line breaks in my file.

Is there no way to specify the character for a line break in scan / read.table / etc.?

Kind regards,

Susanne


-----Opprinnelig melding-----
Fra: David Winsemius [mailto:dwinsemius at comcast.net] 
Sendt: 27. februar 2010 17:38
Til: Balzer Susanne
Kopi: 'r-help at r-project.org'
Emne: Re: [R] scan and skip - without line breaks in the input file


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
>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT