[R] regex question
rv15i at yahoo.se
Tue Aug 4 19:28:10 CEST 2009
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"
## This just retrieves the whole string
## Next trial with gregexpr
## This gives :
 1 7 10 15 20 24 28 31 34
 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.
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