F#: removing duplicates from a seq is slow

Question

I am attempting to write a function that weeds out consecutive duplicates, as determined by a given equality function, from a seq<\'a> but with a twist:

Answer 1

As the other answers have said, seq are really slow. However, the real question is why do you want to use a seq here? In particular, you start with a list and you want to traverse the entire list and you want to create a new list at the end. There doesn't appear to be any reason to use a sequence at all unless you want to use sequence specific features. In fact, the docs state that (emphasis mine):

A sequence is a logical series of elements all of one type. Sequences are particularly useful when you have a large, ordered collection of data but do not necessarily expect to use all the elements. Individual sequence elements are computed only as required, so a sequence can provide better performance than a list in situations in which not all the elements are used.