[R] string concatenate across rows of a matrix??

[Albert Kim]

Dalgaard and Plate suggestions both work.  Thanks for the help.
I was tripped up by not realizing that the optional 'collapse' argument of
paste() must be specified.  Otherwise, it defaults to NULL,  which yields:

	> apply(x2, 1, paste)
	     1   2   3   4
	[1,] "a" "b" "c" "d"
	[2,] "1" "2" "3" "4"
	[3,] "k" "l" "m" "n"

-Al

On 24 Sep 2002, Peter Dalgaard BSA wrote:

> Tony Plate <tplate at blackmesacapital.com> writes:
>
> >  > apply(format(x2), 1, paste, collapse=" ")
> >        1       2       3       4
> > "a 1 k" "b 2 l" "c 3 m" "d 4 n"
>
> ...or even (data frames only):
>
> > do.call("paste",x2)
> [1] "a 1 k" "b 2 l" "c 3 m" "d 4 n"
>
>
> >
> > At 12:45 PM 9/24/2002 -0700, Albert Kim wrote:
> >
> > >Is there a simple way to string-concatenate across the rows of a matrix or
> > >data.frame into a vector of strings?  perhaps using paste() or
> > >something like it?
> > >
> > >That is, I want to map from something like x2 below:
> > >
> > >         > x2 <- data.frame(C1 = letters[1:4], C3=1:4, C3=letters[11:14])
> > >         > x2
> > >           C1 C3 C3
> > >         1  a  1  k
> > >         2  b  2  l
> > >         3  c  3  m
> > >         4  d  4  n
> > >
> > >to something like:
> > >
> > >         [1]  "a  1  k"
> > >         [2]  "b  2  l"
> > >         [3]  "c  3  m"
> > >         [4]  "d  4  n"
> > >
> > >Sincerely,
> > >Al Kim
> > >Research Scientist
> > >Department of Psychology
> > >University of Washington, Box 351525
> > >Seattle, WA. 98195, USA
> > >E-Mail:  alkim at u.washington.edu;  Tel: (206)543-2395
> > >
> > >
> > >
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> --
>    O__  ---- Peter Dalgaard             Blegdamsvej 3
>   c/ /'_ --- Dept. of Biostatistics     2200 Cph. N
>  (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
> ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
>

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