Swift之字符串处理

发表于 分类于

  1. data和string互转：

    1
    2
    3
    4
    // data转string
    let string = String(data:data,encoding:.utf8)
    // string转data
    let data = myString.data(using:.utf8)

  2. json数据中的日期格式处理

    json数据中的日期格式有时不是我们想要的，可以使用encoder.dateEncodingStrategy来设置不同的时间格式来满足需要：

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    struct StudentTime: Codable {
        let registerTime: Date
        
        enum CodingKeys: String, CodingKey {
            case registerTime = "register_time"
        }
    }

    let stu = StudentTime(registerTime: Date())
    encoder.outputFormatting = .prettyPrinted
    var encodedData = try encoder.encode(stu)
    print(String(data: encodedData, encoding: .utf8)!)

    encoder.dateEncodingStrategy = .iso8601
    encodedData = try encoder.encode(stu)
    print(String(data: encodedData, encoding: .utf8)!)

    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    encoder.dateEncodingStrategy = .formatted(formatter)
    encodedData = try encoder.encode(stu)
    print(String(data: encodedData, encoding: .utf8)!)

    //打印结果：
    {
      "register_time" : 573010087.00337005
    }
    {
      "register_time" : "2019-02-28T01:28:07Z"
    }
    {
      "register_time" : "2019-02-28"
    }

    有时服务器返回一个base64编码的数据时，可以设置decoder的dataDecodingStrategy属性为base64来得到原始数据：

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    struct Student: Codable {
        let blog: Data
    }

    let res = """
    {
        "blog": "aHR0cDovL3d3dy5qaWFuc2h1LmNvbS91c2Vycy8zMjhmNWY5ZDBiNTgvdGltZWxpbmU="
    }
    """
    let json = res.data(using: .utf8)!
    let decoder = JSONDecoder()
    decoder.dataDecodingStrategy = .base64
    let stu = try! decoder.decode(Student.self, from: json)
    print(String(data: stu.blog, encoding: .utf8)!)

  3. 截取字符串

    1
    2
    3
    4
    let wholeString = "北京大龄未婚女青年受过高等教育的比例81.1%，大龄未婚男中一半以上初中未毕业。"
    let range = NSRange(location: 2, length: 13)
    let rangeString = (wholeString as NSString).substring(with: range)
    print(rangeString)