[datatable-help] Sub setting multiple ids based on a 2nd data frame

[Matthew Dowle]

Hi,

Good question.  How about :

http://stackoverflow.com/questions/17867553/data-table-join-using-two-columns-from-one-table-and-one-column-from-other
http://stackoverflow.com/questions/17597508/merging-endpoints-of-a-range-with-a-sequence
http://stackoverflow.com/questions/16666183/find-values-in-a-given-interval-without-a-vector-scan

The syntax for range queries is a bit tricky and we hope to make it 
easier in future :

https://r-forge.r-project.org/tracker/index.php?func=detail&aid=203&group_id=240&atid=978

Matthew


On 08/09/13 05:46, guzzom wrote:
> Hi All,
>
> I have some telemetry data that spans multiple years (2002 - 2013) with
> multiple individuals per year. I want to subset the telemetry data to
> include only those data points that fall between specific dates which are
> provided in a 2nd data frame. The telemetry df is in the form of:
>
> DF "A"
>
> ID	Date	         Depth	Temp
> 1	2012-05-12	     10	12
> 1	2012-05-13	     10	12
> 1	2012-05-14	     10	12
> 1	2012-05-15	     10	12
> 2	2012-05-16	     10	12
> 2	2012-05-17	     10	12
> 2	2012-05-18	     10	12
> 2	2012-05-19	     10	12
> 3	2012-05-20	     10	12
> 3	2012-05-21	     10	12
> 3	2012-05-22	     10	12
> 3	2012-05-23	     10	12
> 3	2012-05-24	     10	12
>
> And the df with the dates I want to use to subset is formatted as follows:
>
>   DF "B"
>
> Year	   Start	    End
> 2002	2002-05-10	2002-11-01
> 2003	2003-05-11	2003-11-02
> 2004	2004-05-12	2004-11-03
> 2005	2005-05-13	2005-11-04
> 2006	2006-05-14	2006-11-05
>
> So, I want to say, for each ID in DF A, subset and keep only those data
> points collected on a date that fall between the start and end date for the
> corresponding year from DF B.
>
> I am unsure if a loop is my best bet, or using plyr (which I am unfamiliar
> with). I am relatively new to R, so this seems a bit above my head. Any help
> is much appreciated.
>
> Thanks in advance!
>
>
>
> --
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