Question

如何打印List-Map-String，String--？

例如，我有列表>，我需要打印一对值：购买= 7024.5898或促销= 7764.0203

void main() {


 List<Map < String, String> > data =
 [{"ccy":"USD","base_ccy":"UAH","buy":"23.90000","sale":"25.00000"}, 
 {"ccy":"EUR","base_ccy":"UAH","buy":"26.50000","sale":"27.90000"},
 {"ccy":"RUR","base_ccy":"UAH","buy":"0.35700","sale":"0.40200"},
 {"ccy":"BTC","base_ccy":"USD","buy":"7024.5898","sale":"7764.0203"}];

  data.forEach((key) {
  print(key['ccy']);
});
}

在此变体中，我只能打印一个元素如何打印两个元素？

Answer 1

您可以打印这样的值。

     data.forEach(items -> 
            System.out.println(items.get("buy")+" "+items.get("sale")));

Answer 2

此代码看起来像Java代码。如果您有一个类型为List<Map < String, String> >

的对象

然后您可以打印该对象的值，如下所示：

    for (Map<String, String> myMap : data) {
        for (String key : myMap.keySet()) {

            if((key=="buy" && myMap.get(key)=="7024.5898") ||
                    (key=="sale" && myMap.get(key)=="7764.0203")){
            System.out.println(key +": " + myMap.get(key));
            }
        }

    }

如何打印列表<地图<>>

2 个答案: