[R] aggregating using 'with' function

[AC Del Re]

Perfect! Thanks Jim.

Do you know how I could then reduce the data even further?
Specifically, reducing it to 1 id per row? In this dataset, id 1 would
have one row eliminated.
Assume the data is much larger and cannot be deleted by visual
inspection and elimination one row at a time.


Thank you,

AC

On Sat, Feb 20, 2010 at 6:26 PM, jim holtman <jholtman at gmail.com> wrote:
> This seems to work fine (notice the missing 'c(...)'; why did you think you
> needed it);
>
>>  with(datas,  aggregate(list(r = r),  by = list(id = id, mod1 =
>> mod1),mean))
>    id mod1      r
> 1   1    1  0.980
> 2   4    1  0.640
> 3   7    1  0.490
> 4  10    1  0.180
> 5   1    2  0.295
> 6   5    2  0.490
> 7   8    2  0.330
> 8  11    2  0.600
> 9   6    3 -0.040
> 10  9    3  0.580
> 11 12    3  0.210
>>
>
>
> On Sat, Feb 20, 2010 at 6:54 PM, AC Del Re <delre at wisc.edu> wrote:
>>
>> Hi All,
>>
>> I am interested in aggregating a data frame based on 2
>> categories--mean effect size (r) for each 'id's' 'mod1'. The
>> 'with' function works well when aggregating on one category (e.g.,
>> based on 'id' below) but doesnt work if I try 2 categories. How can
>> this be accomplished?
>>
>> # sample data
>>
>> id<-c(1,1,1,rep(4:12))
>> n<-c(10,20,13,22,28,12,12,36,19,12, 15,8)
>> r<-c(.98,.56,.03,.64,.49,-.04,.49,.33,.58,.18, .6,.21)
>> mod1<-factor(c(1,2,2, rep(c(1,2,3),3)))
>> mod2<-c(1,2,15,rep(3,9))
>> datas<-data.frame(id,n,r,mod1,mod2)
>>
>> # one category works perfect:
>>
>> with(datas,  aggregate(list(r = r),  by = list(id = id),mean))
>>
>>  id          r
>> 1   1  0.5233333
>> 2   4  0.6400000
>> 3   5  0.4900000
>> 4   6 -0.0400000
>> 5   7  0.4900000
>> 6   8  0.3300000
>> 7   9  0.5800000
>> 8  10  0.1800000
>> 9  11  0.6000000
>> 10 12  0.2100000
>>
>> # trying with 2 categories:
>>
>>  with(datas,  aggregate(list(r = r),  by = list(c(id = id, mod1 =
>> mod1)),mean))
>>
>> Error in FUN(X[[1L]], ...) : arguments must have same length
>>
>> Thank you,
>>
>> AC
>>
>> ______________________________________________
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>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem that you are trying to solve?
>