[R] merge function while obviating duplicate columns XXXX

[Dan Abner]

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
>>
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