[R] skip lines on a connection

[Vadim Ogranovich]

Unfortunately, seek only works in terms of bytes not lines and I only
know how many lines I need to skip, but not bytes.


-----Original Message-----
From: Gabor Grothendieck [mailto:ggrothendieck at myway.com] 
Sent: Saturday, May 01, 2004 3:44 PM
To: r-help at stat.math.ethz.ch
Subject: Re: [R] skip lines on a connection




?seek

Vadim Ogranovich <vograno <at> evafunds.com> writes:

: 
: Hi,
: 
: I am looking for an efficient way of skipping big chunks of lines on a
: connection (not necessarily at the beginning of the file). One way is
to
: use read lines, e.g. readLines(1e6), but a) this incurs the overhead
of
: construction of the return char vector and b) has a (fairly remote)
: potential to blow up the memory.
: 
: Another way would be to use scan(), e.g. 
: 
: scan(con, skip=1e6, nmax=0)
: 
: but somehow this doesn't work:
: 
: > scan(con, skip=10, nmax=0)
: Error in scan(con, skip = 10, nmax = 0) : 
:  "scan" expected a real, got "A;12;0;"
: 
: I can stick to readLines, but am curious if there is a better way.
: 
: I use R-1.8.1 on RH-7.3.
: 
: Thanks,
: Vadim

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide!
http://www.R-project.org/posting-guide.html