[R] generating a data frame with a subset from another data frame

[jim holtman]

?"%in%"

I think what you want is:

study.1<-subset(study,study$Species %in% c("ACNE","PLOC","FRAM","ULAM","ACSA2))


On 7/8/07, James R. Milks <james.milks at wright.edu> wrote:
> R gurus,
>
> I have a data set that looks something like this:
>
> Site    Species DBH     #Vines
> G       PLOC    45.9    4
> G       ACNE    23.3    1
> G       ACNE    12.0    0
> G       FRAM    35.9    5
> G       AEGL    11.2    2
> N       PLOC    77.3    12
> N       JUNI    78.6    7
> N       ACNE    18.9    1
> N       ACNE    15.7    3
> N       ACRU    35.5    4
> H       ACSA2   24.1    6
> H       ULAM    35.2    7
>
> There are 730 individual trees (22 species) from four sites in the
> actual data set.  I would like to create a second data frame that
> contains just the most common species (mainly ACNE, PLOC, ULAM, FRAM,
> and ACSA2).  Here's some of my attempts:
>
>  >study.1<-subset(study,study$Species=c
> ("ACNE","PLOC","FRAM","ULAM","ACSA2))
> Error: syntax error
>
>  >study.1<-study[study$Species==,c("ACNE","PLOC","FRAM","ULAM","ACSA2)]
> Error: syntax error
>
>  >study.1<-study[c("ACNE","PLOC","FRAM","ULAM","ACSA2"),]
> #This one appeared to work, but upon inspection, it just copied the
> entire "study" data frame instead of just copying the data I wanted,
> as study.1$Species had a length of 22 (the same as the original)
> instead of the desired length of 5.
>
> I've already consulted a book on R as well as spent the last three
> hours searching the R-help archives.  There must be a way to get the
> subset I desire but it is not obvious to me.
>
> Thanks in advance for your help.
>
> Jim Milks
>
> Graduate Student
> Environmental Sciences Ph.D. Program
> Wright State University
> 3640 Colonel Glenn Hwy
> Dayton, OH 45431
>
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>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?