[R] Splitting a character vector.

Jeff Newmiller jdnewmil at dcn.davis.CA.us
Sun Jul 8 00:12:16 CEST 2012

Just to clarify, the regex engine wants to see a \ before the ( if it is to treat it as an ordinary character. However, the source code interpreter also treats \ as an escape character. In order to get a \ into the string, you have to escape it. So it takes two \ characters in source code to obtain one \ character in memory where the regex code can "see" it.
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Rui Barradas <ruipbarradas at sapo.pt> wrote:

>Try the following.
>open.par <- " \\("  # with a blank before '('
>close.par <- "\\)"
>result <- strsplit(sub(close.par, "", dd1), open.par)
>Why the two '\\'? Because '(' is a meta-character so it must be
>But '\' is a meta character so it must also be escaped.
>Then choose the right way to separate the two, maybe something like
>ix <- rep(c(TRUE, FALSE), length(result))
>Hope this helps,
>Rui Barradas
>Em 07-07-2012 22:37, John Kane escreveu:
>> I am lousy at simple regex and I have not found a solution to a
>simple problem.
>> I have a vector with some character values that I want to split.
>> Sample data
>> dd1  <-  c( "XXY (mat harry)","XXY (jim bob)", "CAMP (joe blow)",
>"ALP (max jack)")
>> Desired result
>> dd2  <-  data.frame( xx = c("XXY", "XXY", "CAMP", "ALP"), yy = c("mat
>harry", "jim bob" , "joe blow", "max jack"))
>> I thought I should be able to split the characters with strsplit but
>either I am misunderstanding the function or don't know how to escape a
>"(" properly in an effort to at least get   "XXY" "(mat harry)"
>> Any pointers would be appreciated
>> Thanks
>> John Kane
>> Kingston ON Canada
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