[R] value matching %in% for a number pair

[John]

Hi,

   We can match one numerical value as follows
> 3 %in% c(4,5)
[1] FALSE
> 3 %in% c(4,5,3)
[1] TRUE

   To see whether value pairs are identical,
> identical(c(3,4), c(3,5))
[1] FALSE
> identical(c(3,4), c(3,4))
[1] TRUE

   Is there any way to test whether “A value pair is in a set of value
pairs”? For example, can we test whether the pair (2,3) is identical to one
of the pairs in the set S={(1,2), (4,3), (3,3), (2,3), (4,5)}?
   In this case, the answer is yes because the 4th element of S is (2,3).
Is there any simple way to code it? Thanks!

John

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