R help - Feb 2007 - 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

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
> 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.
Petr Pikal
petr.pikal at precheza.cz