[R] R - Populate Another Variable Based on Multiple Conditions | For a Large Dataset

Kevin Wamae KWamae at kemri-wellcome.org
Sun Jul 3 19:24:51 CEST 2016


HI Jeff, it’s been an uphill task working with the dataset and I am not the first to complain. Nonetheless, data-cleaning is ongoing and since I cannot wait for that to get done, I decided to make the most of what the dataset looks like at this time. It appears the process may take a while.

Thanks for the script. From the output, I noticed that “result” contains the first and last date for each of the individuals and not taking into account the variable “drug-admin”. 

ID	    start		end
J1/3	    1/5/09	12/25/10
R1/3	    1/4/07	12/15/08
R10/1	    1/4/07	3/5/12

My aim is to pick the date, for example in 2007, where drug-admin == “Y” as my start and the date in the subsequent year (2008 in this case) where drug-admin == “Y” as my end. Then, I should populate the variable “study_id” with “start” up to the entry just above the one whose date matches “end”, as the output below shows (I hope its structure is maintained as I have copied it from R-Studio). The goal for now is to then get difference in days between “date” and “study_id” and still get to keep that column for “study_id” as I might use it later.

From the output, it can be seen that for this individual, the dates run from 2007 to 2008. However, for some individuals, the dates run from 2008-2009, 2009-2010 and so on. Therefore, I need to make the script deal with all the years as the dates range from 2001-2016

ID	date	drug_admin	year	month	study_id
R1/3	5/11/07	Y	2007	5	5/11/07
R1/3	5/16/07		2007	5	5/11/07
R1/3	5/22/07		2007	5	5/11/07
R1/3	5/28/07		2007	5	5/11/07
R1/3	6/5/07			2007	6	5/11/07
R1/3	6/11/07		2007	6	5/11/07
R1/3	6/18/07		2007	6	5/11/07
R1/3	6/25/07		2007	6	5/11/07
R1/3	7/2/07			2007	7	5/11/07
R1/3	7/16/07		2007	7	5/11/07
R1/3	7/29/07		2007	7	5/11/07
R1/3	8/2/07			2007	8	5/11/07
R1/3	8/7/07			2007	8	5/11/07
R1/3	8/13/07		2007	8	5/11/07
R1/3	9/18/07		2007	9	5/11/07
R1/3	9/24/07		2007	9	5/11/07
R1/3	10/6/07		2007	10	5/11/07
R1/3	10/8/07		2007	10	5/11/07
R1/3	10/15/07		2007	10	5/11/07
R1/3	10/22/07		2007	10	5/11/07
R1/3	10/29/07		2007	10	5/11/07
R1/3	11/8/07		2007	11	5/11/07
R1/3	11/12/07		2007	11	5/11/07
R1/3	11/19/07		2007	11	5/11/07
R1/3	11/29/07		2007	11	5/11/07
R1/3	12/6/07		2007	12	5/11/07
R1/3	12/10/07		2007	12	5/11/07
R1/3	12/21/07		2007	12	5/11/07
R1/3	1/7/08			2008	1	5/11/07
R1/3	1/14/08		2008	1	5/11/07
R1/3	1/21/08		2008	1	5/11/07
R1/3	1/28/08		2008	1	5/11/07
R1/3	2/4/08		Y	2008	2	


Regards
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Kevin Wame 

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On 7/3/16, 7:05 PM, "Jeff Newmiller" <jdnewmil at dcn.davis.ca.us> wrote:

result <- setNames( data.frame( aggregate( date~ID, data=drug_study, FUN=min ),  aggregate( date~ID, data=drug_study, FUN=max )[2] ), c( "ID", "start", "end" ) )


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