[R] merge function while obviating duplicate columns XXXX

Jeff Newmiller jdnewmil at dcn.davis.CA.us
Mon Mar 11 22:19:23 CET 2013


intersect(names(data1),names(data2))
---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live Go...
                                      Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
--------------------------------------------------------------------------- 
Sent from my phone. Please excuse my brevity.

Dan Abner <dan.abner99 at gmail.com> wrote:

>Ok, let's say I only want the common columns from data1. Is there a
>succinct way of doing this for potentially hundreds of "in common"
>columns?
>
>
>
>On Mon, Mar 11, 2013 at 3:25 PM, Ista Zahn <istazahn at gmail.com> wrote:
>> On Mon, Mar 11, 2013 at 3:17 PM, Dan Abner <dan.abner99 at gmail.com>
>wrote:
>>> Hi everyone,
>>>
>>> I have the following call to the merge() function. How does one
>>> prevent duplicate columns in the resulting data frame that the 2
>>> parent data frames have in common but are not true key or "by"
>>> variables?
>>>
>>>
>>> data3<-merge(data1,data2,by="id")
>>> data3
>>>
>>> id total.x total.y balance
>>> 1 78  78 90
>>> 2 91  91 63
>>> 3 74  74 57
>>> 4 89  89 58
>>> 5 90  90 27
>>>
>>>
>>> In this example, total is not a true key or "by" variable that
>>> uniquely identifies rows suitable for matching purposes, but instead
>>> just happens to be common to both sets.
>>
>> Well, which one do you want? Or do you want to exclude total from the
>result?
>>
>>>
>>> In reality, I have hundreds for these "in common" variables, so I
>need
>>> a solution that is tractable for a large number of "in common"
>>> columns.
>>>
>>> Thanks!
>>>
>>> Dan
>>>
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>
>______________________________________________
>R-help at r-project.org mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.



More information about the R-help mailing list