filter_func.go

package main

import "golang.org/x/exp/slices"

func FilterFunc[T any](list []T, keep func(T) bool) []T {
	filtered := make([]T, 0, len(list))
	for _, e := range list {
		if keep(e) {
			filtered = append(filtered, e)
		}
	}
	return slices.Clip(filtered)
}