On Sep 19, 2011, at 7:05 AM, Sarah Goslee wrote:
Hi,
On Mon, Sep 19, 2011 at 6:15 AM, SNV Krishna <kris...@primps.com.sg>
wrote:
Hi All,
I have a character vector by name tickers
head(tickers,10)
V1
1 ADARSHPL.BO
2 AGR.V
3 AGU
4 AGU.TO
5 AIMCO.BO
6 ALUFLUOR.BO
7 AMZ.V
8 AVD
9 ANILPROD.BO
10 ARIES.BO
I would like to extract all elements that has ".BO" in it. I tried
grep("\.BO",tickers)
Error: '\.' is an unrecognized escape in character string starting
"\."
You need instead:
tickers <- c("A.BO", "BOB", "C.BO")
grep("\\.BO", tickers)
[1] 1 3
tickers[grep("\\.BO", tickers)]
[1] "A.BO" "C.BO"
grep(".BO",tickers)
[1] 1
That's odd; it should have returned many more matches. You may need to
check the format of your data.
There are two NOT-oddities at work here. Periods and other special
characters need to be doubly escaped when used as literals in search
patterns, and the vector that needs to be searched is not "tickers"
but rather "tickers$V1".
That result is because there is only one element in the list named
"tickers" and grep finds that it does have an instance that matches
the pattern. (Despite that fact that it is not searching what the OP
thought he was searching for but rather a more general pattern.)
--
David.
Could any one please guide me on this. Many thanks for the help
Best Regards,
Krishna
--
Sarah Goslee
http://www.functionaldiversity.org
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David Winsemius, MD
West Hartford, CT
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
