[R] how to create data.frames from vectors with duplicates

[Bert Gunter]

Inline below:

On Wed, Aug 31, 2011 at 9:50 AM, Jorge I Velez <jorgeivanvelez at gmail.com> wrote:
> Hi Zhenjiang,
>
> Try
>
> table(unlist(mapply(function(x, y) rep(x, y), y, x)))

Yikes! How about simply tapply(x,y,sum) ??
?tapply

-- Bert
>
> HTH,
> Jorge
>
>
> On Wed, Aug 31, 2011 at 12:45 PM, zhenjiang xu <> wrote:
>
>> Hi R users,
>>
>> suppose I have two vectors,
>>  > x=c(1,2,3,4,5)
>>  > y=c('a','b','c','a','c')
>> How can I get a data.frame like this?
>> > xy
>>      count
>> a     5
>> b     2
>> c     8
>>
>> I know a few ways to fulfill the task. However, I have a huge number
>> of this kind calculations, so I'd like an efficient solution. Thanks
>>
>> --
>> Best,
>> Zhenjiang
>>
>> ______________________________________________
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>> 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.
>>
>
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>
> ______________________________________________
> 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.
>