arrays - 如何在Dart中对该数组/映射进行排序？

Question

如何从Dart中的“数据”对 map /数组进行排序？

var training = [
  {"data" : "15/10/2019" , "pic" : "assets/images/foto3.jpg"},
  {"data" : "10/10/2019" , "pic" : "assets/images/foto5.jpg"},
  {"data" : "15/10/2019" , "pic" : "assets/images/foto4.jpg"},
  {"data" : "30/10/2019" , "pic" : "assets/images/bocateam.jpg"},
  {"data" : "17/10/2019" , "pic" : "assets/images/foto2.jpg"},
];

Answer 1

我不确定您要排序的内容，但我会根据“数据”值猜测是按日期排序。请看一下此实现，并告诉我是否有您不了解的内容:

void main() {
  final training = [
    {"data": "15/10/2019", "pic": "assets/images/foto3.jpg"},
    {"data": "10/10/2019", "pic": "assets/images/foto5.jpg"},
    {"data": "15/10/2019", "pic": "assets/images/foto4.jpg"},
    {"data": "30/10/2019", "pic": "assets/images/bocateam.jpg"},
    {"data": "17/10/2019", "pic": "assets/images/foto2.jpg"},
  ];

  training.sort((map1, map2) {
    final date1 = parseDate(map1['data']);
    final date2 = parseDate(map2['data']);
    return date1.compareTo(date2);
  });

  training.forEach(print);
  //  {data: 10/10/2019, pic: assets/images/foto5.jpg}
  //  {data: 15/10/2019, pic: assets/images/foto3.jpg}
  //  {data: 15/10/2019, pic: assets/images/foto4.jpg}
  //  {data: 17/10/2019, pic: assets/images/foto2.jpg}
  //  {data: 30/10/2019, pic: assets/images/bocateam.jpg}
}

// Format: 15/10/2019
DateTime parseDate(String date) {
  final parts = date.split('/');
  return DateTime(
      int.parse(parts[2]), int.parse(parts[1]), int.parse(parts[0]));
}

如果每个日期都首先转换为 DateTime对象，则实现可能会更高效，因此我们在排序时不需要多次转换每个对象。但是，如果 list 很短，那不是主要问题。