[R] Trying to replicate error message in subset()

Petr Pikal
Mon, 12 Feb 2007 07:46:52 -0000

Hi

it is not error it is just warning (Beeping a tea kettle with boiling
water is also not an error :-)
and it tells you pretty explicitly what is wrong
see length of your objects

> a<-c("D", "F", "A")
> new.dat<-subset(ex.dat, x1 == a)
Warning messages:
1: longer object length
        is not a multiple of shorter object length in: is.na(e1) |
is.na(e2)
2: longer object length
        is not a multiple of shorter object length in:
`==.default`(x1, a)
> new.dat
            y1 x1 x2
3    0.5977786  A  B
6    2.5470739  A  B
9    0.9128595  A  B
12   1.0953531  A  D
15   2.4984470  A  D
18   1.7289529  A  D
61  -0.4848938  D  B
6

you can do better with %in% operator.

HTH
Petr



On 12 Feb 2007 at 1:51, Michael Rennie wrote:

Date sent:      	Mon, 12 Feb 2007 01:51:54 -0500
To:             	r-help at stat.math.ethz.ch
From:           	Michael Rennie <mrennie at utm.utoronto.ca>
Subject:        	[R] Trying to replicate error message in subset()

>
> Hi, there
>
> I am trying to replicate an error message in subset() to see what it
> is that I'm doing wrong with the datasets I am trying to work with.
>
> Essentially, I am trying to pass a string vector to subset() in order
> to select a specific collection of cases (i.e., I have data for these
> cases in one table, and want to select data from another table that
> match up with the cases in the first table).
>
> The error I get is as follows:
>
> Warning messages:
> 1: longer object length
>          is not a multiple of shorter object length in: is.na(e1) |
>          is.na(e2)
> 2: longer object length
>          is not a multiple of shorter object length in:
>          `==.default`(LAKE, g)
>
> Here is an example case I've been working with (which works) that
I've
> been trying to "break"such that I can get this error message to
figure
> out what I am doing wrong in my case.
>
> y1<-rnorm(100, 2)
> x1<-rep(1:5, each=20)
> x2<-rep(1:2, each=10, times=10)
>
> ex.dat<-data.frame(cbind(y1,x1,x2))
>
>
> ex.dat$x1<-factor(ex.dat$x1, labels=c("A", "B",
"C", "D", "E"))
> ex.dat$x2<-factor(ex.dat$x2, labels=c("B", "D"))
>
> a<-c("D", "F")
> a
>
> new.dat<-subset(ex.dat, x1 == a)
> new.dat
>
> I thought maybe I was getting errors because I had cases in my
> selection vector ('a' in this case) that weren't in my ex.dat
list,
> but subset handles this fine and just gives me what it can find in the
> larger list.
>
> Any thoughts on how I can replicate the error? As far as I can tell,
> the only difference between the case where I am getting errors and the
> example above is that the levels of x1 in my case are words (i.e.,
> "Smelly", "Howdy"), but strings are strings, aren't
they?
>
> Mike
>
>
> Michael Rennie
> Ph.D. Candidate, University of Toronto at Mississauga
> 3359 Mississauga Rd. N.
> Mississauga, ON  L5L 1C6
> Ph: 905-828-5452  Fax: 905-828-3792
> www.utm.utoronto.ca/~w3rennie
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
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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 at precheza.cz