Question

我在下面有一个示例代码：

z = [] //To get all the Id    
x = [
        {
           _id: "12345",
           name: "A"      
        },
        {
           _id: "67890",
           name: "B"
        }
    ]

问题是如何才能获得所有＆＃34; _id＆＃34;来自＆＃34; x＆＃34;并将其保存到＆＃34; z＆＃34;。结果如下：

z = ["12345", "67890"]

任何答案都将不胜感激

Answer 1

这是一个非常简单的Array#map()

＆＃13;

public class FileUtil {
    private Logger logger = Logger.getLogger(FileUtil.class);

    public List<String> loadDataSet(String fileName) {

        List<String> stringsFromFile = new ArrayList<>();
        String str = "";

        //  ClassLoader.getResourceAsStream
        try (InputStream is = getClass().getClassLoader().getResourceAsStream(fileName)) {
            //System.out.println(is);
             BufferedReader reader = new BufferedReader(new InputStreamReader(is));

            if (is != null) {
                while ((str = reader.readLine()) != null) {
                    stringsFromFile.add(str);
                }
            }

        } catch (FileNotFoundException e) {
            logger.error(e);
        } catch (IOException e1) {
            logger.error(e1);
        }

        return stringsFromFile;
    }
}

＆＃13;

Answer 2

使用 array.map

var  x = [
        {
           "_id": "12345",
           "name": "A"      
        },
        {
           "_id": "67890",
           "name": "B"
        }
    ];
var result = x.map(a => a._id);
console.log(result);

在Array Node JS中获取多个对象中的特定键

2 个答案: