more helper functions

map.go

@@ -0,0 +1,9 @@
+package slices
+
+func Map[I, O any](slice []I, mapper func(I) O) []O {
+	ret := make([]O, 0, len(slice))
+	for _, v := range slice {
+		ret = append(ret, mapper(v))
+	}
+	return ret
+}