numExtract.swift

let digs: Set<Character> = ["1", "2", "3", "4", "5", "6", "7", "8", "9", "0"]

extension String {
  var firstNum: Int? {
    return self
      .characters
      .indexOf(digs.contains)
      .map(characters.suffixFrom)
      .flatMap { cs in
        Int(String(cs.prefixUpTo(cs.indexOf { c in !digs.contains(c) } ?? cs.endIndex)))
    }
  }
}