[R] Do grep() and strsplit() use different regex engines?

[Jeff Newmiller]

"\\b" is a zero length match. strsplit seems to chop at least one character off the beginning of the string if it sees a match, and then it looks at the shortened string that remains and repeats.
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Sent from my phone. Please excuse my brevity.

On July 11, 2015 7:47:22 AM PDT, Bert Gunter <bgunter.4567 at gmail.com> wrote:
>I noticed the following:
>
>> strsplit("red green","\\b")
>[[1]]
>[1] "r" "e" "d" " " "g" "r" "e" "e" "n"
>
>> strsplit("red green","\\W")
>[[1]]
>[1] "red"   "green"
>
>I would have thought that "\\b" should give what "\\W" did. Note that:
>
>> grep("\\bred\\b","red green")
>[1] 1
>## as expected
>
>Does strsplit use a different regex engine than grep()? Or more
>likely, what am I misunderstanding?
>
>Thanks.
>
>Bert
>
>
>Bert Gunter
>
>"Data is not information. Information is not knowledge. And knowledge
>is certainly not wisdom."
>   -- Clifford Stoll
>
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