[R] Extracting subsets by factor level?

[Peter Dalgaard]

Rory.WINSTON at rbs.com wrote:
> Hi
>
> I have a data frame which looks like the following (it is a table of commit logs to a source repo). The Author column
> is treated as a factor, by virtue of stringsAsFactors being set to TRUE, so I can extract the number of commits
> per author by using table(logs$Author).
>
> Is there an elegant way to extract all subsets of this frame by the Author column - i.e. that returns say a list of
> data frames, each containing just the records for a specific value of Author?
>   
Yup:

split(logs, logs$Author)

> Thanks
> Rory
>
>   
>> head(logs)
>>     
>
>   Revision Author                Date LinesChanged
> 1        6 user1  13/11/2007 15:41:53          488
> 2       11 user1 14/11/2007 09:04:43            3
> 3       12 user2 16/11/2007 12:26:04          522
> 4       13 user1 16/11/2007 12:27:55           90
> 5       14 user3 19/11/2007 09:32:54          159
> 6       15 user1 21/11/2007 13:38:41         1986
>
>
>
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