[R] matching type question, please

[Rui Barradas]

Hello,

And here is another solution, addressing the problem raised by Bert and 
avoiding unique.


xr1 <- 8:0
xr2 <- 0:8
xs1 <- 9:3
xs2 <- 4
cbind(xr1, xr2)[(xr1 %in% xs1) & (xr2 %in% xs2),]
#xr1 xr2
#  4   4


xr1 <- c(1,2,1)
xr2 <- c(4,5,4)
xs1 <- c(6,6)
xs2 <- c(7,7)
cbind(xr1, xr2)[(xr1 %in% xs1) & (xr2 %in% xs2),]
#   xr1 xr2
(only column names are output)


But this only works if the vectors xr* are longer than xs*. Try swapping 
the test values (both sets, Erin's original and Bert's) and see.

So here is a function that checks lengths first, then takes the right 
branch.


dupSpecial <- function(x1, x2, y1, y2){
   if(length(x1) > length(y1)){
     cbind(x1, x2)[(x1 %in% y1) & (x2 %in% y2),]
   } else {
     cbind(y1, y2)[(y1 %in% x1) & (y2 %in% x2),]
   }
}
dupSpecial(xr1, xr2, xs1, xs2)


Hope this helps,

Rui Barradas


Às 22:01 de 16/12/21, Bert Gunter escreveu:
> I am not sure Eric's solution is what is wanted:
> 
> Consider:
> xr1 <- c(1,2,1)
> xr2 <- c(4,5,4)
> xs1 <- c(6,6)
> xs2 <- c(7,7)
> 
>> z1 <- cbind(xr1, xr2)
>> z2 <- cbind(xs1,xs2)
>> z1
>       xr1 xr2
> [1,]   1   4
> [2,]   2   5
> [3,]   1   4
>> z2
>       xs1 xs2
> [1,]   6   7
> [2,]   6   7
> 
> If what is wanted is to find rows of z2 that match those in z1, Eric's
> proposal gives (note the added comma to give a logical indexing
> vector):
> 
>> a <- cbind(c(xr1,xs1),c(xr2,xs2))
>> a[duplicated(a),]
>       [,1] [,2]
> [1,]    1    4
> [2,]    6    7
> 
> This is obviously wrong, as it gives duplicates *within* z1 and z2,
> not between them. To get rows of z2 that appear as duplicates of rows
> of z1, then something like the following should do:
> 
>> a <- rbind(unique(z1),unique(z2))
>> a
>       xr1 xr2
> [1,]   1   4
> [2,]   2   5
> [3,]   6   7
>> a[duplicated(a),]
>       xr1 xr2
> ## nothing
> 
> I leave it to Erin to determine whether this is relevant to her
> problem and, if so, how to fix up my suggestion appropriately.
> 
> Cheers,
> Bert Gunter
> 
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
> 
> On Thu, Dec 16, 2021 at 12:39 PM Eric Berger <ericjberger using gmail.com> wrote:
>>
>>> a <- cbind(c(xr1,xs1),c(xr2,xs2))
>>> a[duplicated(a)]
>> [1] 4 4
>>
>>
>> On Thu, Dec 16, 2021 at 10:18 PM Erin Hodgess <erinm.hodgess using gmail.com> wrote:
>>>
>>> Hello!
>>>
>>> I have the following:
>>>
>>>   cbind(xr1,xr2)
>>>
>>>        xr1 xr2
>>>
>>>   [1,]   8   0
>>>
>>>   [2,]   7   1
>>>
>>>   [3,]   6   2
>>>
>>>   [4,]   5   3
>>>
>>>   [5,]   4   4
>>>
>>>   [6,]   3   5
>>>
>>>   [7,]   2   6
>>>
>>>   [8,]   1   7
>>>
>>>   [9,]   0   8
>>>
>>>> cbind(xs1,xs2)
>>>
>>>       xs1 xs2
>>>
>>> [1,]   9   4
>>>
>>> [2,]   8   4
>>>
>>> [3,]   7   4
>>>
>>> [4,]   6   4
>>>
>>> [5,]   5   4
>>>
>>> [6,]   4   4
>>>
>>> [7,]   3   4
>>>
>>>>
>>>
>>> These are ordered pairs.  I would like to get something that shows that the
>>> pair (4,4) appears in both.  I have tried cbind with match and %in% and
>>> intersect, but not getting the exact results.
>>>
>>> Any suggestions would be appreciated.  I have a feeling that it's something
>>> really easy that I'm just not seeing.
>>>
>>> Thanks,
>>> Erin
>>>
>>>
>>> Erin Hodgess, PhD
>>> mailto: erinm.hodgess using gmail.com
>>>
>>>          [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> 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.
>>
>> ______________________________________________
>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.
> 
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
>