[R] Group by in R

[Peter Dalgaard]

Mike Lawrence wrote:
> One way:
> 
> g= paste(f1,f2,f3,f4)
> table(g)

I'd go for

g <- interaction(f1,f2,f3,f4, drop=TRUE)
table(g)

which is essentially the same thing.

> 
> On Mon, Apr 13, 2009 at 7:33 AM, Nick Angelou <nikolay12 at yahoo.com> wrote:
>> Hi,
>>
>> I have the following table data:
>>
>> f1, f2, f3, f4.
>>
>> I want to compute the counts of unique combinations of f1-f4. In SQL I would
>> just write:
>>
>> SELECT COUNT(*) FROM <table> GROUP BY f1, f2, ..,f4.
>>
>> How to do this in R?
>>
>> Thanks,
>>
>> Nick
>> --
>> View this message in context: http://www.nabble.com/Group-by-in-R-tp23020587p23020587.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
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>>
> 
> 
> 


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