Jonathan -
split will do what you want:
> df <-
data.frame('id'=c('a','b','a','c','b','a'),'value'=c(6,4,2,9,1,7))
> split(df$value,df$id)
$a
[1] 6 2 7
$b
[1] 4 1
$c
[1] 9
Thanks for providing a reproducible example!
- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
spector at stat.berkeley.edu
On Fri, 12 Feb 2010, Jonathan Reichel wrote:
> Hi all,
> Another one:
>
> Given a data frame with two columns, where the first column (let's
> call it 'id') has redundant entries, I'd like to get, for each
unique
> value in 'id', a list or vector of all the values from the second
> column that corresponded to that value.
>
> Example:
>
>> df <-
data.frame('id'=c('a','b','a','c','b','a'),'value'=c(6,4,2,9,1,7))
>> df
> id value
> 1 a 6
> 2 b 4
> 3 a 6
> 4 c 9
> 5 b 1
> 6 a 7
>
> I'd like some kind of output resembling something along these lines:
>
> a: 6, 6, 7
> b: 4, 1
> c: 9
>
> Any ideas would be appreciated!
>
> Best,
> Jonathan
>
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