Filter filters a slice of E's according to a predicate.

Reject rejects a slice of E's according to a predicate.

RejectNils rejects in-place all nil elements from a slice of E's and returns the number of elements rejected.

RejectZero rejects in-place all zero-valued elements from a slice of E's and returns the number of elements rejected.

Builder is a builder for slices.

Predicate is a function that returns true if the element is valid.