[R] pattern search

Uwe Ligges ligges at statistik.uni-dortmund.de
Fri Oct 29 20:27:27 CEST 2004

Sean Liang wrote:

> hi, I like to find a pattern within a giver sequence. There might be
> multiple occurences of the pattern. I like to know the number of
> occurences and the positions if possible. "grep" can tell me if a
> pattern exists but can't give me the information I need. Does anyone
> know any function that I can use or know how to do what I intend?.


   gr <- grep("a", c("a", "b", "a"))

grep tells you that the positions are 1 and 3. length(gr) tells you 
there are two occurences.

Uwe Ligges

> Thanks a lot.
> Sean
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