[R] Dataframe by Serial ID

[Jeff Newmiller]

"merge" is generally the base R answer to this question, and there are equivalent functions in various contributed packages.

However, it is necessary to identify which columns in each table uniquely identify each row ("primary key"). If your Serial 3036 shows up 10 times in the first table and 10 times in the second table then you will end up with all combinations of those rows (100 rows) in a merge that uses only Serial to match rows. Is that what you want?


On January 8, 2020 6:52:18 AM PST, Thomas Subia <tsubia using imgprecision.com> wrote:
>Colleagues,
>
>I have two data frames which look like this.
>
>Data frame 1
>
>  	Serial 	Pre.Hole 	Pre.flow  	Pre.Date
>1   	3036        1     		0.24 		19-Nov-19
>2   	3036        2    		0.212 		19-Nov-19
>3   	3036        3    		1.292 		19-Nov-19
>4   	3036        4    		0.262 		19-Nov-19
>5   	3036        5    		1.291 		19-Nov-19
>6   	3036        6     		0.26 		19-Nov-19
>
>Data frame 2
>
>      	Serial	 Post.Hole 	Post.flow 	Post.Date
>62323  11024        44    		-0.678 		11-Dec-19
>62324  11024        45    		-0.659 		11-Dec-19
>62325  11024        46   		 -0.654 		11-Dec-19
>62326  11024        47    		-0.699 		11-Dec-19
>62327  11024        48   		 -0.671 		11-Dec-19
>62328  11024        49    		-0.687 		11-Dec-19
>
>What I want is to create a data frame whose serials numbers are common
>to data frames 1 and 2.
>The resulting data frame 1st row would look like this.
>
>Serial 	Post.Hole 	Post.flow 	Post.Date	Pre.Hole 	Pre.flow 	Pre.Date
>
>Any ideas on how to do this would be appreciated.
>
>Thomas Subia 
>Statistician / Senior Quality Engineer
>
>IMG Companies 
>225 Mountain Vista Parkway
>Livermore, CA 94551
>T. (925) 273-1106
>F. (925) 273-1111
>E. tsubia using imgprecision.com
>
>
>Precision Manufacturing for Emerging Technologies
>imgprecision.com 
>
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