R help - Aug 2009 - What is the returned type of strsplit?

Hi,

I run the following program. I thought that 'b' was a matrix. But it
is actually not, right? Can somebody elaborate more on the type
difference between 'b' and 'c' to help me understand it better?

Why 'c' is what it is now? Why 'c' is not the transpose of what
it is now?

Regards,
Peng

$ Rscript split.R
> a=array(c('a,b','c,d','e,f'),c(3))
> a[[1]]
[1] "a,b"
> a
[1] "a,b" "c,d" "e,f"
> b=strsplit(a,split=',')
> b[[1]]
[1] "a" "b"
> b
[[1]]
[1] "a" "b"

[[2]]
[1] "c" "d"

[[3]]
[1] "e" "f"
> c=sapply(b,function(x){x[1:2]})
> c
     [,1] [,2] [,3]
[1,] "a"  "c"  "e"
[2,] "b"  "d"  "f"
>

On Sun, 16-Aug-2009 at 10:40AM -0500, Peng Yu wrote:

|> Hi,
|> 
|> I run the following program. I thought that 'b' was a matrix. But
it
|> is actually not, right? Can somebody elaborate more on the type
|> difference between 'b' and 'c' to help me understand it
better?
|> 
|> Why 'c' is what it is now? Why 'c' is not the transpose of
what it is now?
|> 
|> Regards,
|> Peng
|> 
|> $ Rscript split.R
|> > a=array(c('a,b','c,d','e,f'),c(3))
|> > a[[1]]
|> [1] "a,b"
|> > a
|> [1] "a,b" "c,d" "e,f"
|> > b=strsplit(a,split=',')
|> > b[[1]]
|> [1] "a" "b"
|> > b
|> [[1]]
|> [1] "a" "b"
|> 
|> [[2]]
|> [1] "c" "d"
|> 
|> [[3]]
|> [1] "e" "f"
|> 
|> > c=sapply(b,function(x){x[1:2]})
|> > c
|>      [,1] [,2] [,3]
|> [1,] "a"  "c"  "e"
|> [2,] "b"  "d"  "f"


I think your question is about sapply, not strsplit.  It "simplifies"
and if it's going to make a matrix, it will set byrow to FALSE.  

HTH


-- 
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