And _file()_ is helpful in such situation. R/S-PLUS Fundamentals and Programming Techniques by Thomas Lumley has something relavant in page 185 (total page is 208).
I believe you can find it by googling. On 4/6/07, Martin Becker <[EMAIL PROTECTED]> wrote: > readLines (which is mentioned in the "See also" section of ?scan with > the hint "to read a file a line at a time") should work. > > Regards, > Martin > > Yuchen Luo schrieb: > > Hi, my friends. > > When a data file is large, loading the whole file into the memory all > > together is not feasible. A feasible way is to read one row, process it, > > store the result, and read the next row. > > > > > > In Fortran, by default, the 'read' command reads one line of a file, which > > is convenient, and when the same 'read' command is executed the next time, > > the next row of the same file will be read. > > > > I tried to replicate such row-by-row reading in R.I use scan( ) to do so > > with the "skip= xxx " option. It takes only seconds when the number of the > > rows is within 1000. However, it takes hours to read 10000 rows. I think it > > is because every time R reads, it needs to start from the first row of the > > file and count xxx rows to find the row it needs to read. Therefore, it > > takes more time for R to locate the row it needs to read. > > > > Is there a solution to this problem? > > > > Your help will be highly appreciated! > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > [email protected] 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. > > > > ______________________________________________ > [email protected] 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. > -- Ronggui Huang Department of Sociology Fudan University, Shanghai, China ______________________________________________ [email protected] 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.
