将长弦弦解析为lat & long s颤振

Question

我从Json中的API调用接收Lats & Longs的String。

"lineStrings": [
        "[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057],[-0.267972,51.494627],[-0.254555,51.495148],[-0.245704,51.494917],[-0.235881,51.494122],[-0.22362,51.4923],[-0.213427,51.490311],[-0.206636,51.490459],[-0.193378,51.492063],[-0.182658,51.494316],[-0.174138,51.494094],[-0.156377,51.49227],[-0.143102,51.496359],[-0.133608,51.499544],[-0.124861,51.50132],[-0.122666,51.507058],[-0.11426,51.511006],[-0.103659,51.511581],[-0.094009,51.512117],[-0.090432,51.51151],[-0.085969,51.5107],[-0.076546,51.509971],[-0.072384,51.515037],[-0.059971,51.519518],[-0.046596,51.521858],[-0.03364,51.525122],[-0.025128,51.52694],[-0.011538,51.524839],[0.005055,51.528136],[0.017451,51.531341],[0.035263,51.53534],[0.051186,51.538948],[0.081053,51.539321],[0.10153,51.538372],[0.127016,51.540331],[0.147527,51.541639],[0.166017,51.544096],[0.19864,51.549775],[0.219116,51.554093],[0.235809,51.55856],[0.250882,51.559063]]]"]

与我习惯的调用不同，它们不是我可以迭代的单个lat和long值，它作为一个长字符串块返回。

我可能不正确，但我不相信我能够解析它，因为没有lat & long类可以迭代，只有lineStrings，这是一个很长的块。我要解析的Quicktype.io类在迭代时带我到.linestrings

我想把它们分割成坐标对，这样我就可以从每个坐标中取lat & long。

我试过‘拆分’，但是由于双打之间的逗号，我无法让它工作。我也尝试删除特殊字符，但无法保持格式化。

欢迎任何建议。

最终目标是能够执行以下操作

for (var x in coordinates){
GeoCoordinates y = GeoCoordinates(x.latitude, x.longitude);
}

谢谢

Answer 1

您必须手动拆分：

void main() {
  '[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057]]]'
      .split('],[')
      .forEach((p) => print(p.replaceAll('[', '').replaceAll(']', '')));
}

指纹：

-0.301457,51.515017
-0.288265,51.51014
-0.280462,51.503057

您可以在,上进一步拆分，并将其解析为一对双倍。

或者您可以添加一个LatLong类来保存这一对：

void main() {
  final latLongs =
      '[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057]]]'
          .split('],[')
          .map((p) => LatLong.fromString(
                p.replaceAll('[', '').replaceAll(']', ''),
              ));

  print(latLongs);
}

class LatLong {
  LatLong(this.lat, this.long);

  factory LatLong.fromString(String pair) {
    final parts = pair.split(',');
    return LatLong(double.parse(parts[0]), double.parse(parts[1]));
  }

  double lat;
  double long;
}

Answer 2

var json = {"lineStrings": [
                    "[[[-0.301457,51.515017],[-0.288265,51.51014],[-0.280462,51.503057],[-0.267972,51.494627],[-0.254555,51.495148],[-0.245704,51.494917],[-0.235881,51.494122],[-0.22362,51.4923],[-0.213427,51.490311],[-0.206636,51.490459],[-0.193378,51.492063],[-0.182658,51.494316],[-0.174138,51.494094],[-0.156377,51.49227],[-0.143102,51.496359],[-0.133608,51.499544],[-0.124861,51.50132],[-0.122666,51.507058],[-0.11426,51.511006],[-0.103659,51.511581],[-0.094009,51.512117],[-0.090432,51.51151],[-0.085969,51.5107],[-0.076546,51.509971],[-0.072384,51.515037],[-0.059971,51.519518],[-0.046596,51.521858],[-0.03364,51.525122],[-0.025128,51.52694],[-0.011538,51.524839],[0.005055,51.528136],[0.017451,51.531341],[0.035263,51.53534],[0.051186,51.538948],[0.081053,51.539321],[0.10153,51.538372],[0.127016,51.540331],[0.147527,51.541639],[0.166017,51.544096],[0.19864,51.549775],[0.219116,51.554093],[0.235809,51.55856],[0.250882,51.559063]]]"
                  ]
                };


                List<dynamic> jsonList = json["lineStrings"]!
                    .first
                    .replaceAll("[", "")
                    .replaceAll("]", "")
                    .split(",");


                List<Coordinates> result = [];
                for (var i = 0; i < jsonList.length / 2; i++) {
                  result.add(Coordinates(
                      lat: double.parse(jsonList[i]),
                      long: double.parse(jsonList[i + 1])));
                }


                result.forEach((element) {
                  print("Lat" + element.lat.toString());
                  print("Long" + element.long.toString());
                  print("*************************");
                });

class Coordinates {
      double lat;
      double long;

  Coordinates({
    required this.lat,
    required this.long,
 });
 }

颤振: Lat-0.301457

颤振: Long51.515017

颤振：*

颤振: Lat51.515017

颤振:长-0.288265

颤振：*

颤振: Lat-0.288265

颤振: Long51.51014

颤振：*