Re: [R] Presence/ absence data from matrix to single column

Rui Barradas Sun, 07 Oct 2012 17:03:34 -0700

Hello,

If all your species have different names, you can allways try one of

1. if the non-species follow a pattern, negate those columns and you'llhave the species columns.

2. are the species the last columns? Use positional referencing.


Rui Barradas
Em 08-10-2012 00:16, Andrea Goijman escreveu:

Ill try this one as well.

And I guess the one below is not going  to work, because all my species
have different names.

Thanks!

#nms <- names(adat)
nms <- c("Year", "Route", "Point", paste0("Sp", 1:250))

pattern <- "^Sp[[:digit:]]+$"
whichCols <- grep(pattern, nms)
whichNames <- nms[whichCols]

reshape(..., varying = whichCols, times = whichNames, ...)
On Sun, Oct 7, 2012 at 3:02 PM, arun <smartpink...@yahoo.com> wrote:

Hi,
I guess you are not talking about the melt() method.
dat1<-read.table(text="
Year    Route    Point    Sp1    Sp2    Sp3
2004    123    123-1    0    1    0
2004    123    123-2    0    1    1
2004    123    123-10    1    1    0
",header=TRUE,sep="",stringsAsFactors=FALSE)


#If all the Sp columns are located next to another as shown in your
example dataset, then you can also try this:
name1<-unlist(strsplit(paste(colnames(dat1)[4:6],collapse=" ")," "))
reshape(dat1,varying=4:6,v.name
="Sp-value",times=name1,timevar="Sp-name",idvar=c("Year","Route","Point"),direction="long")

A.K.






----- Original Message -----
From: Rui Barradas <ruipbarra...@sapo.pt>
To: agoijman <agoij...@cnia.inta.gov.ar>
Cc: r-help@r-project.org
Sent: Sunday, October 7, 2012 2:32 PM
Subject: Re: [R] Presence/ absence data from matrix to single column

Hello,

I haven't been following this thread but apparently the answer to your
worries is no.
You can use a combination of names() and grep() to sort it out.
something like

#nms <- names(adat)
nms <- c("Year", "Route", "Point", paste0("Sp", 1:250))

pattern <- "^Sp[[:digit:]]+$"
whichCols <- grep(pattern, nms)
whichNames <- nms[whichCols]

reshape(..., varying = whichCols, times = whichNames, ...)


Hope this helps,

Rui Barradas
Em 07-10-2012 15:35, agoijman escreveu:

The problem with that, is that I just wrote an example of my database,

but I

have around 250 species and more than 500 sites. In the approach you show
me, it looks like I have to enter every species name and sites

individually,

right?



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Re: [R] Presence/ absence data from matrix to single column

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