[R] Finding values in one column and

[John Kane]

Come to think of it the plyr package and the data.table packages also offer similar tools.  For large merges (joins) I think the data.table package is much faster.

John Kane
Kingston ON Canada


> -----Original Message-----
> From: steven.ranney at gmail.com
> Sent: Tue, 27 Nov 2012 15:28:57 -0700
> To: jrkrideau at inbox.com
> Subject: Re: [R] Finding values in one column and
> 
> Thanks.
> 
> Soon after I posted this question, I discovered merge().
> 
> Steven H. Ranney
> 
> 
> On Tue, Nov 27, 2012 at 3:26 PM, John Kane <jrkrideau at inbox.com> wrote:
>> Have a look at ?merge
>> 
>> John Kane
>> Kingston ON Canada
>> 
>> 
>>> -----Original Message-----
>>> From: steven.ranney at gmail.com
>>> Sent: Tue, 27 Nov 2012 15:17:58 -0700
>>> To: r-help at r-project.org
>>> Subject: [R] Finding values in one column and
>>> 
>>> All -
>>> 
>>> I have a data frame
>>> 
>>> data.a
>>> ID    valueA  valueB
>>> 6     12      12
>>> 17    15      14
>>> 58    18      16
>>> 98    11      12
>>> 73    19      20
>>> 84    19      14
>>> 58    20      14
>>> 24    11      12
>>> 81    15      16
>>> 21    15      14
>>> 62    14      12
>>> 67    13      14
>>> 78    13      17
>>> 35    10      13
>>> 13    11      15
>>> 14    17      18
>>> 85    16      15
>>> 35    13      9
>>> 18    15      16
>>> 
>>> and a data frame
>>> 
>>> data.b
>>> ID    valueA  valueB
>>> 6
>>> 84
>>> 21
>>> 78
>>> 14
>>> 
>>> I'd like to have R find the data.b$ID in data.a$ID and insert the
>>> corresponding data.a$valueA and data.a$valueB into the appropriate
>>> columns in data.b.
>>> 
>>> How can I do this?
>>> 
>>> Thanks for you help.
>>> 
>>> SR
>>> Steven H. Ranney
>>> 
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>> 
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