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$xxx) to get sum of xxx (=28) satisfying the
criteria where xx == 10 etc
Please enlighten my problem.
thanks
On Mon, Aug 24, 2009 at 12:19 PM, David Winsemius <[email protected]>wrote:
>
> On Aug 23, 2009, at 10:12 PM, David Winsemius wrote:
>
>
>> On Aug 23, 2009, at 9:56 PM, Steven Kang wrote:
>>
>> Dear R users,
>>>
>>> I am using "subset" function to filter out specific conditions and would
>>> like to use the value of subsetted argument as a name of an object.
>>>
>>> Specifically, from the following statement:
>>>
>>> a <- subset(dat, dat$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
>
>
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