Re: [R] subscripting issues

From: Petr Pikal <petr.pikal_at_precheza.cz>
Date: Thu 25 Jan 2007 - 17:53:49 GMT

Hi

On 25 Jan 2007 at 10:44, Marc Schwartz wrote:

From:           	Marc Schwartz <marc_schwartz@comcast.net>
To:             	ablukacz <ablukacz@utm.utoronto.ca>
Date sent:      	Thu, 25 Jan 2007 10:44:18 -0600
Copies to:      	r-help@stat.math.ethz.ch
Subject:        	Re: [R] subscripting issues
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> On Thu, 2007-01-25 at 11:04 -0500, ablukacz wrote:
> > Dear All,
> >
> > I have a very simple problem.
> > I have a matrix called Predictors with headers X0...X24
> > >dim(Predictors)
> > [1] 79 25
> >
> > Predictors
> > X0 X1 X2 X3 X4 X5
> > X6
> > 1 13.741200 12.148036 11.909435 11.671669 11.238207 10.864697
> > 10.566351 2 10.240200 11.883900 11.529400 11.515050 11.411640
> > 11.105800 10.813457
> >
> >
> >
> > I would like to take each row and all the corresponding columns with
> > out the header. I tried Predictors[1,1:25] but that retains the
> > headers.
> >
> >
> > Any suggestions.
> >
> > Thanks,
> >
> > Agnes
>
> The column names of X0, etc. suggest that Predictors is a data frame
> created by the use of one of the read.table() family of functions, not

although you are probably right, it could be matrix as well

> is.data.frame(zeta)

[1] TRUE
> is.matrix(zeta)

[1] FALSE

>

> zetam<-as.matrix(zeta)
> zetam

  tepl tio2 al2o3 iep
1   60    1   3.5 5.65
2   60    1   2.0 5.00
3   60    0   3.5 5.30
4   60    0   2.0 4.65
5   40    1   3.5 5.20
6   40    1   2.0 4.85
7   40    0   3.5 5.70
8   40    0   2.0 5.25

> is.matrix(zetam)

[1] TRUE
> is.data.frame(zetam)

[1] FALSE Cheers
Petr

> a matrix. An important difference depending upon what you intend to do
> with the data.
>
> However, in both cases, you can generally manipulate the data as if
> the headers were not present. In other words, most R functions will
> take the numeric values and act in a predictable (sorry for the pun)
> fashion.
>
> Think of the output above as if the column names X0 through X6 were A
> through G in a spreadsheet. They are simply labels, not part of the
> data itself. The same goes for the row names of 1 and 2.
>
> HTH,
>
> Marc Schwartz
>
> ______________________________________________
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> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html and provide commented,
> minimal, self-contained, reproducible code.

Petr Pikal
petr.pikal@precheza.cz



R-help@stat.math.ethz.ch 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. Received on Fri Jan 26 05:00:56 2007

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