Hi,
here are some solutions:
DF <- read.table(textConnection("
A B C
1 1 3
1 1 4
1 1 5
1 2 6
1 2 7
1 3 8 "), header=TRUE)
#using sqldf package
library(sqldf)
sqldf("select A, B, count(*)
from DF
group by A, B
order by count(*) desc")
#using function table
as.data.frame(table(DF$A, DF$B))
As you can see, you can use sqldf package for performing sql queries
on R data frames.
Andrija
On Tue, Apr 3, 2012 at 8:26 PM, Steven Raemaekers <s.raemaek...@sig.eu> wrote:
> Hi,
>
> I have a query which I would like to translate into R, but I do not know how
> to do it in an easy way.
> Assume a data frame has columns A, B and C:
>
> A B C
> 1 1 3
> 1 1 4
> 1 1 5
> 1 2 6
> 1 2 7
> 1 3 8
>
> The query is as follows:
>
> select A, B, count(*)
> from data.frame
> group by A, B
> order by count(*) desc
>
> How do I translate this into R statements in such way that the result is a
> data frame structured as follows:
>
> A B count(*)
> 1 1 3
> 1 2 2
> 1 3 1
>
> Thanks,
>
> Steven
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