[R] grep and strings

Spencer Graves spencer.graves at pdf.com
Tue Apr 27 02:06:12 CEST 2004

How about the following: 

 > tst <- c(".a.", "asdf")
 > sum(regexpr("\\.a\\.", tst)>0)
[1] 1

      hope this helps.  spencer graves

K Fung wrote:

>I have the following command:
>  grep("\.a\.", names(temp)))
>where temp is a vector with names
>I want to count the number of entries that contain the
>sequence of characters ".a.".  However, R seems to
>return all entries that contain "a" (every entry
>contains "." in this example).
>How should I fix this?  Thanks
>R-help at stat.math.ethz.ch mailing list
>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

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