[R] Ids with matching number combinations?

PIKAL Petr petr@p|k@| @end|ng |rom prechez@@cz
Fri Oct 7 16:02:01 CEST 2022

Hallo Marine

Could you please make your example more reproducible by using set.seed (and
maybe smaller)?

If I understand correctly, you want to know if let say row 1 items from df2
(8,16) are both in item column of specific id?

If I am correct in guessing, I cannot find another solution than split your
df according to id
x <- split(df, df$id)[[1]]

and for each row of df2 test if within the specified id you can find both
sum(is.element(df2[1,], x$item))==2

So basically 2 cycles, one for df ids and the other for df2 rows.

But maybe somebody will give you more ingenious answer.


> -----Original Message-----
> From: R-help <r-help-bounces using r-project.org> On Behalf Of Marine Andersson
> Sent: Friday, October 7, 2022 1:58 PM
> To: r-help using r-project.org
> Subject: [R] Ids with matching number combinations?
> Hi,
> If I have two datasets like this:
> df=data.frame("id"=rep(1:10,10, each=10), "item1"=sample(1:20, 100,
> replace=T)
> df2=data.frame("a"=c(8, 8,10,9, 5, 1,2,1), "b"=c(16,18,11, 19,18,
> How do I find out which ids in the df dataset that has a match for both
> numbers occuring in the same row in the df2 dataframe? In the output I
> like to get the matching id and the rownumber from the df2.
> Output something like this
> Id                        Rownr
> 2                         1
> 5                         1
> 7                         4
> My actual problem is more complex with even more columns to be matched and
> the datasets are large, hence the solution needs to be efficient.
> Kind regards,
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