Sangick Jeon <sijeon <at> ucdavis.edu> writes:
> Is there a way to use regular expressions to capture two or more words in a
> sentence? For example, I wish to to find all the lines that have the
words "thomas",
> "perl", and "program", such as "thomas uses a program called perl", or "perl
is a
> program that thomas uses", etc.
If you only have two patterns to search for then a regular expression can
be done this way:
data(state)
grep("i.*n|n.*i", state.name) # states with i and n in name
but it gets unwieldy if you have three since there are 6 permutations, not 2.
In that case, you are probably better off iterating greps like this:
lookfor <-
function(pat, x) { for(p in pat) x <- grep(p, x, value = TRUE); x }
lookfor(c("i","n","g"), state.name) # states with i, n and g in name
______________________________________________
[EMAIL PROTECTED] mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
