takeWhileL is:exact

where <math> is the prefix length. takeWhileL, applied to a predicate p and a sequence xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p.

where <math> is the prefix length. takeWhileL, applied to a predicate p and a sequence xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p. Returns a possibly empty sequence (Seq) in the case that the predicate fails on the first item.