R help - Jun 2010 - subset dataset using factor levels instead of factor names

Hi All,

I have a factor variable with 52 levels -with long, annoying names.  I want to
keep only rows with some variables.  I can do this using this code:

test1 <- subset(nih2009,ic_name %in% c('NATIONAL EYE
INSTITUTE','Veterans Affairs'))
dim(test1)

[1] 2396   38

But this doesn't work:

t1 <- subset(nih2009, ic_name %in% c(27,51))
dim(t1)
[1]  0 38


I know there's a way to do this.  Any help?  Thanks,

Rachel

	[[alternative HTML version deleted]]

Rachel -
    Not exactly a reproducible example, but maybe


t1 <- subset(nih2009, ic_name %in% levels(nih2009$ic_name)[c(27,51)])


 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Tue, 22 Jun 2010, Hayes, Rachel M wrote:
> Hi All,
>
> I have a factor variable with 52 levels -with long, annoying names.  I want
to keep only rows with some variables.  I can do this using this code:
>
> test1 <- subset(nih2009,ic_name %in% c('NATIONAL EYE
INSTITUTE','Veterans Affairs'))
> dim(test1)
>
> [1] 2396   38
>
> But this doesn't work:
>
> t1 <- subset(nih2009, ic_name %in% c(27,51))
> dim(t1)
> [1]  0 38
>
>
> I know there's a way to do this.  Any help?  Thanks,
>
> Rachel
>
> 	[[alternative HTML version deleted]]
>
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