Thank, Eik, it works!

-Jack

On Wed, Aug 17, 2011 at 9:19 AM, Eik Vettorazzi <
E.Vettorazzi@uke.uni-hamburg.de> wrote:

> Hi Jack,
> yes there is. see ?read.table for option check.names
>
> and to the 2nd task "." is a special character in regular expressions,
> so mask it or don't use regular expressions:
>
> gregexpr("[.]","A.B.C.D") #or
> gregexpr(".","A.B.C.D",fixed=T)
>
> cheers.
>
> Am 17.08.2011 15:03, schrieb Jack Luo:
> > Hi,
> >
> > I have a silly question regarding the usage of two commands: read.table
> and
> > gregexpr：
> > For read.table, if I read a matrix and set header = T, I found that all
> the
> > dash ("-") becomes dots (".")
> >
> >
> > A = read.table("Matrix.txt", sep = "\t", header = F)
> > A[1,1]
> > # "A-B-C-D".
> >
> > A = read.table("Matrix.txt", sep = "\t", header = T)
> > colnames(A)[1]
> > # "A.B.C.D"
> >
> > Is there a way to use the header = T argument, but still keep the
> original
> > format "A-B-C-D"?
> >
> > For gregexpr,
> > gregexpr("-","A-B-C-D")[[1]]
> > #[1] 2 4 6
> > #attr(,"match.length")
> > #[1] 1 1 1
> >
> >
> > gregexpr(".","A.B.C.D")[[1]]
> > [1] 1 2 3 4 5 6 7
> > attr(,"match.length")
> > [1] 1 1 1 1 1 1 1
> >
> > Looks like dots means all the characters. Is there a way that I can
> extract
> > the position of the dots specifically?
> >
> > Thanks,
> >
> > -Jack
> >
> >       [[alternative HTML version deleted]]
> >
> >
> >
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
> --
> Eik Vettorazzi
> Institut für Medizinische Biometrie und Epidemiologie
> Universitätsklinikum Hamburg-Eppendorf
>
> Martinistr. 52
> 20246 Hamburg
>
> T ++49/40/7410-58243
> F ++49/40/7410-57790
>

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