R help - Aug 2008 - Parenthesis recognition with grep

Dear R-users,

I need to dynamically recognize the index of a given string myStr in a 
vector of string. The problem is that myStr might contain parenthesis, 
causing grep not to recognize it the way I want (see below). The help 
mentions that the pattern used by grep should be in the POSIX format... 
I guess the problem is here; unfortunately, I am not familiar with the 
subtleties of the POSIX format

ex:
myStr <- "YD(001)"
headers <-c("TD", "YD(001)", "YD(002)",
"T", "Y(001)", "Y(002)")
grep(myStr, headers)

How should I modify my grep call to get the match right?

Thank you for your help,

Sebastien

Dear Sébastien,

Is this what you want?

which(myStr==headers)
[1]  2

which(headers%in%myStr)
[1] 2


HTH,

Jorge



On Sun, Aug 31, 2008 at 10:28 AM, Sébastien <pomchip@free.fr> wrote:
> Dear R-users,
>
> I need to dynamically recognize the index of a given string myStr in a
> vector of string. The problem is that myStr might contain parenthesis,
> causing grep not to recognize it the way I want (see below). The help
> mentions that the pattern used by grep should be in the POSIX format... I
> guess the problem is here; unfortunately, I am not familiar with the
> subtleties of the POSIX format
>
> ex:
> myStr <- "YD(001)"
> headers <-c("TD", "YD(001)", "YD(002)",
"T", "Y(001)", "Y(002)")
> grep(myStr, headers)
>
> How should I modify my grep call to get the match right?
>
> Thank you for your help,
>
> Sebastien
>
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