[R] Subsetting a square marix

David L Carlson dcarlson at tamu.edu
Tue Jan 5 19:23:08 CET 2016

```Assuming I've reconstructed your data correctly:

> dta
Sp1 Sp2 Sp3 Sp4 Sp5 Sp6
Sp1   0   1   0   0   0   0
Sp2   0   0   0   1   0   0
Sp3   1   0   0   0   1   0
Sp4   0   0   1   1   0   1
Sp5   0   1   0   0   0   1
Sp6   0   0   0   0   0   0
> dput(dta)
structure(list(Sp1 = c(0L, 0L, 1L, 0L, 0L, 0L), Sp2 = c(1L, 0L,
0L, 0L, 1L, 0L), Sp3 = c(0L, 0L, 0L, 1L, 0L, 0L), Sp4 = c(0L,
1L, 0L, 1L, 0L, 0L), Sp5 = c(0L, 0L, 1L, 0L, 0L, 0L), Sp6 = c(0L,
0L, 0L, 1L, 1L, 0L)), .Names = c("Sp1", "Sp2", "Sp3", "Sp4",
"Sp5", "Sp6"), class = "data.frame", row.names = c("Sp1", "Sp2",
"Sp3", "Sp4", "Sp5", "Sp6"))

The results of dput(dta) is what you should include in your plain text email.

As for the subset, your email indicated: sp1, sp3 and spp. But none of these are labels in your data set since R is case sensitive. Try for example:

> sub <- c("Sp1", "Sp3", "Sp5")
> dta[sub, sub]
Sp1 Sp3 Sp5
Sp1   0   0   0
Sp3   1   0   1
Sp5   0   0   0

And definitely spend some time with the available free R tutorials so that you understand how R works.

-------------------------------------
David L Carlson
Department of Anthropology
Texas A&M University
College Station, TX 77840-4352

-----Original Message-----
From: R-help [mailto:r-help-bounces at r-project.org] On Behalf Of Sarah Goslee
Sent: Tuesday, January 5, 2016 10:15 AM
To: Tawanda Tarakini
Cc: r-help
Subject: Re: [R] Subsetting a square marix

It really isn't clear what you want, and posting in HTML has mangled
what you did provide.

Please use dput() to provide sample data, and give us a clear idea of
what you want, ideally an example of what the output should look like.
Adding the R code you've tried to use is also a good idea.

Sarah

On Tue, Jan 5, 2016 at 4:06 AM, Tawanda Tarakini
<tawandatizora at gmail.com> wrote:
> I have a global matrix (e.g. table below) of species feeding. I am trying
> to create specific matrix for specific sites. If for example a subset is to
> have sp1, sp3 and spp only these 3 species should be appearing in the
> subset (both column and rows).
>
> I have been checking online help but I seem not to get my scenario
>
>
>
> Sp1
>
> Sp2
>
> Sp3
>
> Sp4
>
> Sp5
>
> Sp6
>
> Sp1
>
> 0
>
> 0
>
> 1
>
> 0
>
> 0
>
> 0
>
> Sp2
>
> 1
>
> 0
>
> 0
>
> 0
>
> 1
>
> 0
>
> Sp3
>
> 0
>
> 0
>
> 0
>
> 1
>
> 0
>
> 0
>
> Sp4
>
> 0
>
> 1
>
> 0
>
> 1
>
> 0
>
> 0
>
> Sp5
>
> 0
>
> 0
>
> 1
>
> 0
>
> 0
>
> 0
>
> Sp6
>
> 0
>
> 0
>
> 0
>
> 1
>
> 1
>
> 0
>
> --
> Kind Regards
>
> Tawanda Tarakini
>
> Lecturer and Industrial attachment coordinator
> Department of Wildlife, Ecology and Conservation
> Chinhoyi University of Technology
> Bag 7724, Chinhoyi
> Cell: +263 775 321 722
> Alternative email: ttarakini at cut.ac.zw
>
>         [[alternative HTML version deleted]]
>

--
Sarah Goslee
http://www.numberwright.com

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