let stringA = "123@456" let stringB = "123＠456" let rangeA = stringA.range(of: "@[0-9]", options: .regularExpression, range: nil, locale: nil) //.some let rangeB = stringB.range(of: "@[0-9]", options: .regularExpression, range: nil, locale: nil) //nil

.range ならNS通らなくて済むからできそうですね