Not sure it's exactly what you want but you could use gregexpr. If you're
worried about your search string starting within your search string (like
your example) then maybe you could find one match at a time, mask it out
with gsub, and loop until you don't have any more matches:


search<-'cc'
mask<-search
#replace first character of search string with an arbitrary junk character
substring(mask,1,1)<-'#'
string<-'cccaccc'
found<-c()
while(any(grepl(search,string))){
 found<-c(found,regexpr(search,string))
 #mask out the match we just found
 string<-sub(search,mask,string)
}
print(found)



Scott

Scott Sherrill-Mix
Department of Microbiology
University of Pennsylvania
402B Johnson Pavilion
3610 Hamilton Walk
Philadelphia, PA  19104-6076
Phone: 215-573-3141


On Mon, Jul 20, 2009 at 4:43 AM, kevinchang <shukai@seas.upenn.edu> wrote:

>
> Hi R users,
>
>
> I am trying generate the indices for locating a in the string it come from.
> Given the length of the string, it will take too long using the combn() for
> further comparison. I am wondering if R has any built-in function for this
> purpose.
>
> To make it concrete:
>
> this.substring="cc"
>
> this.string="ccc"
>
> start.location=1,2
> end.location=2,3
>
> Thanks in advance,
> Kevin
>
>
>
>
>
> --
> View this message in context:
> http://www.nabble.com/locate-substring-in-the-string-it-belong-to-tp24565937p24565937.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>

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