> I built a 1,273,230 by 6 data set named "mydata2", it was saved in the > following command, > > write.table(mydata2, "mydata2.txt", row.name=F,col.name=T,quote=F,sep="\t") > > The next day I read in above saved text file into R, > > temp<-read.table("mydata2.txt",header=T,sep="\t",na.strings="NA") > > However, the dimension of "temp" is 636,615 X 6.
A wild guess: does your table contain strings which include single or double ticks? As you are not disabling quoting in read.table this can cause problems: > foo = data.frame(a=c("abc","5'foo","xxx", "3'bar"), b=1:4) > foo a b 1 abc 1 2 5'foo 2 3 xxx 3 4 3'bar 4 > write.table(foo, "mydata2.txt", row.name=F,col.name=T,quote=F,sep="\t") > foo <- read.table("mydata2.txt",header=T,sep="\t",na.strings="NA") > foo a b 1 abc 1 2 5foo\t2\nxxx\t3\n3bar 4 > foo <- read.table("mydata2.txt",header=T,sep="\t",na.strings="NA", quote='') > foo a b 1 abc 1 2 5'foo 2 3 xxx 3 4 3'bar 4 The same aplies to comment characters embedded in strings. If this is not your problem, I'd first check if the file has the expected number of lines. cu Philipp -- Dr. Philipp Pagel Lehrstuhl für Genomorientierte Bioinformatik Technische Universität München Wissenschaftszentrum Weihenstephan 85350 Freising, Germany http://mips.gsf.de/staff/pagel ______________________________________________ R-help@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.