[R] Regular expression help

Duncan Murdoch murdoch.duncan at gmail.com
Mon Oct 9 17:02:40 CEST 2017


I have a file containing "words" like


a

a/b

a/b/c

where there may be multiple words on a line (separated by spaces).  The 
a, b, and c strings can contain non-space, non-slash characters. I'd 
like to use gsub() to extract the c strings (which should be empty if 
there are none).

A real example is

"f 147/1315/587 2820/1320/587 3624/1321/587 1852/1322/587"

which I'd like to transform to

" 587 587 587 587"

Another real example is

"f 1067 28680 24462"

which should transform to "   ".

I've tried a few different regexprs, but am unable to find a way to say 
"transform words by deleting everything up to and including the 2nd 
slash" when there might be zero, one or two slashes.  Any suggestions?

Duncan Murdoch



More information about the R-help mailing list