[R] replace a whole word with sub()

[Gabor Grothendieck]

Here are two ways:

> s <- c("xxx", "yyy", "zzz", "IgA", "IgG", "kkk", "IgM", "aaa")
>
> sub("^Ig.*", "0", s)
[1] "xxx" "yyy" "zzz" "0"   "0"   "kkk" "0"   "aaa"
>
> replace(s, grepl("^Ig", s), "0")
[1] "xxx" "yyy" "zzz" "0"   "0"   "kkk" "0"   "aaa"


On Fri, Nov 13, 2009 at 10:13 AM, Giulio Di Giovanni
<perimessaggini at hotmail.com> wrote:
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>
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> Dear all,
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>
>
> I cannot figure out how to solve a small problem (well, not for me), surely somebody can help me in few seconds.
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>
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> I have a series of strings in a vector X of the type  "xxx", "yyy", "zzz", "IgA", "IgG", "kkk", "IgM", "aaa".
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> I want to substitute every ENTIRE string beginning with "Ig" with "0".
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> So, I'd like to have "xxx", "yyy", "zzz", "0", "0", "kkk", "0", "aaa".
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>
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> I can easily identify these strings with grep("^Ig", X), but if I use this criterion in the sub() function (sub("^Ig", "0", X) I obviously get "0A", "0G" etc.
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> I didn't expect to do it in this way and I tried with metacharacters and regexps in order to grep and substitute the whole word (\b \>, $). I don't post here my tryings,  because they were obviously wrong.
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> Please can you help me?
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>
>
> Giulio
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