[R] Assigning value of subset argument in "subset" function
David Winsemius
dwinsemius at comcast.net
Mon Aug 24 05:23:41 CEST 2009
On Aug 23, 2009, at 10:51 PM, Steven Kang wrote:
> David, apreciate for your help.
>
> However, the result is not what I was expecting.
>
> Following on from your code, for example say the input is:
>
> a <- data.frame(x=rep(1:4,2), y=rep(4:7,2), xx=rep(8:11,2),
> xxx=rep(12:15,1))
>
> x y xx xxx
> 1 1 4 8 12
> 2 2 5 9 13
> 3 3 6 10 14
> 4 4 7 11 15
> 5 1 4 8 12
> 6 2 5 9 13
> 7 3 6 10 14
> 8 4 7 11 15
>
> Using the following "subset" function:
>
> sub.a <- subset(a, xx == 8)
>
> results in:
>
> x y xx xxx
> 1 1 4 8 12
> 5 1 4 8 12
>
> Now, I would like to assign the value of subsetted argument (i.e 8
> in this case) to be able to use repetitively with other values.
> For example,
>
> sub.a.8 <- sum(sub.a$xxx) to get sum of xxx (=24) satisfying
> the criteria where xx = 8
>
> sub.a.9 <- sum(sub.a$xxx) to get sum of xxx (=26) satisfying
> the criteria where xx == 9
> sub.a.10 <- sum(sub.a$xxx) to get sum of xxx (=28) satisfying
> the criteria where xx == 10 etc
> assign(paste("sub.a", 10, sep="."), sum(subset(a, xx==10)$xxx) )
> assign(paste("sub.a", 9, sep="."), sum(subset(a, xx==9)$xxx) )
> assign(paste("sub.a", 8, sep="."), sum(subset(a, xx==8)$xxx) )
> sub.a.8; sub.a.9; sub.a.10
[1] 24
[1] 26
[1] 28
>
> Please enlighten my problem.
>
> thanks
>
>
>
>
> On Mon, Aug 24, 2009 at 12:19 PM, David Winsemius <dwinsemius at comcast.net
> > wrote:
>
> On Aug 23, 2009, at 10:12 PM, David Winsemius wrote:
>
>
> On Aug 23, 2009, at 9:56 PM, Steven Kang wrote:
>
> Dear R users,
>
> I am using "subset" function to filter out specific conditions and
> would
> like to use the value of subsetted argument as a name of an object.
>
> Specifically, from the following statement:
>
> a <- subset(dat, dat$x == "A" & dat$xx == 1 & dat$xxx == "AB" & dat
> $y
> == "B" & dat$yy == 2)
> I would to assign the value of the 3rd subset argument (i.e. "AB")
> as an
> object's name such as:
>
> a.AB <- sum(a$z)
>
> Sounds like you need to read FAQ 7.21:
>
> http://cran.r-project.org/doc/FAQ/R-FAQ.html#How-can-I-turn-a-string-into-a-variable_003f
>
> Perhaps, ... lightly tested, of course, because no reproducible data
> provided:
>
> assign( paste("a.", sum(a$z), sep=""),
> subset(dat,x == "A" & xx == 1 & xxx == "AB" & y== "B" & yy ==
> 2) )
>
> # you do not need the "dat$"'s in the subset.
>
> > a <- data.frame(x=1:4, y=4:7, xx=8:11, xxx=12:15)
> > a
> x y xx xxx
> 1 1 4 8 12
> 2 2 5 9 13
> 3 3 6 10 14
> 4 4 7 11 15
>
> Arrgh. Trimmed out the code:
>
> assign( paste("a.", sum(a$x), sep=""),
> subset(a,x == 1 & xx == 8 ) )
>
>
>
> > a.10
> x y xx xxx
> 1 1 4 8 12
> --
>
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
>
>
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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