skip lines on a connection
On 1 May 2004 at 16:35, Vadim Ogranovich wrote:
Unfortunately, seek only works in terms of bytes not lines and I only know how many lines I need to skip, but not bytes.
read.table() has a skip= agrument (probably also has scan() ) Kjetil Halvorsen
-----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
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