Collection of F# string functions

String.fsx

let isNotEmpty s = not (String.IsNullOrEmpty s)
let join (ss: string seq) = String.Join("", ss)
let lower (s: string) = s.ToLowerInvariant()
let trim (s: string) = s.Trim()
let replace (oldValue: string) newValue (s: string) = s.Replace(oldValue,newValue)
let split (by: string) (s: string) = s.Split(by)
let endsWith (tail: string) (s: string) = s.EndsWith(tail)
let startsWith (head: string) (s: string) = s.StartsWith(head)
let contains (search: string) (s: string) = s.Contains(search)