从a类型数组Angular 7的数组中访问数据

Question

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我声明了一个subject []类型的数组，并从api获取信息，然后将subject推入Arr数组。我的控制台看起来像附件中的图片。我想使用angular访问主题，当我尝试使用this.subject时，它返回未定义。

所以它不是数组中的数组，我需要一些帮助来访问这些数据，我将使用它来从图表js中动态地在图形上创建标签。

Arr: Subject [] = new Array();
 
loadSubjects() {
  this.ss.getSubjects().subscribe(( subject: Subject[]) => {
    this.subject = subject;
    for (let i = 0; i < this.subject.length; i++) {
        this.subjArray.push(this.subject[i]['name']);
    }
  });
}

Answer 1

这可以使用map函数来完成

柱塞解决方案的Click here

还添加了下面的代码：

this.list1 = [
  {Name: "abc", Capacity: "150", Series: "20", Make: "150", Model: "150", TowerHeight: "151"},
  {Name: "def", Capacity: "250", Series: "250", Make: "250", Model: "252", TowerHeight: "250"},
  {Name: "ghi", Capacity: "151", Series: "21", Make: "151", Model: "151", TowerHeight: "152"}
  ];


this.list2 = this.list1.map(item => { return item.Name});

在你的情况下，我想会是这样的

this.subjArray = this.subject.map(item => { return item.name});

输出

列表1:

[
    {
        "Name": "abc",
        "Capacity": "150",
        "Series": "20",
        "Make": "150",
        "Model": "150",
        "TowerHeight": "151"
    },
    {
        "Name": "def",
        "Capacity": "250",
        "Series": "250",
        "Make": "250",
        "Model": "252",
        "TowerHeight": "250"
    },
    {
        "Name": "ghi",
        "Capacity": "151",
        "Series": "21",
        "Make": "151",
        "Model": "151",
        "TowerHeight": "152"
    }
]

列表2:

[ "abc", "def", "ghi" ]

这也可以使用for循环来完成。但是，对于需要在数组中获取单个属性值的图表数据场景，在angular中映射会更简单