[R] regex question

[Gabor Grothendieck]

Try this:

> library(gsubfn)
> strapply(astr, "\\w+", ~ substr(x, 1, 1), simplify = c)
 [1] "T" "i" "m" "t" "o" "w" "t" "d" "i" "i" "t" "f" "f" "T"


On Tue, Aug 4, 2009 at 1:28 PM, ravi<rv15i at yahoo.se> wrote:
>
> Hi,
> I am getting stuck over an apparently simple problem in the use of regular expressions :
> To collect together the first letters of the words from the Perl motto, “There is more than one way to do it” in the following form – TIMTOWTDI.
> I tried the following code :
>
> ##### A regex problem with the Perl motto
> astr<-"There is more than one way to do it"
> b1<-grep("\\<", astr,value=T)
> ## This just retrieves  the whole string
> ## Next trial with gregexpr
> b2<-gregexpr("\\<",astr)
> ## This gives  :
>> b3
> [[1]]
> [1]  1  7 10 15 20 24 28 31 34
> attr(,"match.length")
> [1] 0 0 0 0 0 0 0 0 0
>
> A vector of indices corresponding to the first letter is obtained all right with gregexpr but the next step is not so clear. I am not able to figure out how I can use this information to pick out the letters from the original string. My problem is that I don’t know how I can treat the string as a vector and pluck out the letters.
>
> There may be many ways to do it, but I have not succeeded in coming up with even one way! I will appreciate any tips that I can get.
> Thanking you,
> Ravi
>
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