Question

I would guess this is a duplicate, but I can’t find that so here goes…

I’d like to return the index of second in first:

first = c( "a" , "c" , "b" )
second = c( "c" , "b" , "a" )
result = c( 2 , 3 , 1 )

I guarantee that first and second have unique values, and the same values between the two.

Answer 1

Getting indexes of values is what match() is for.

 first = c( "a" , "c" , "b" )
 second = c( "c" , "b" , "a" )
 match(second, first)
 [1] 2 3 1