[R] Read every second line from ASCII file

From: Roland Rau <roland.rproject_at_gmail.com>
Date: Mon, 30 Apr 2007 14:36:50 -0400


Dear all,

I have an ASCII file where records are separated by a blank. I would like to read those data; however, only the data in rows 1, 3, 5, 7, ... are important; the other lines (2,4,6,8,....) contain no useful information for me.
So far I used awk/gawk to do it:
gawk '{if ((FNR % 2) != 0) {print $0}}' infile.txt > outfile.txt

What is the recommended way to accomplish this in R? Simply reading the whole file, and deleting all the even-numbered lines is not straightforward since these lines have different length (whereas lines 1,3,5,7,... have the same length).

I 'RSiteSearched' for "read every second line from a file" but this search did not yield the desired result.
Also trying out the arguments nrows and skip from read.table() did not help.

Maybe someone knows an easy way to do it from within R? -- of course not using system("gawk ....") :-)
If not, it does not matter too much since I get the job done easily with awk.

Thanks,
Roland

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