Question

我试图遍历项目数组并推送到另一个数组，但项目列表中的索引为“ 0”，但仍然能够获得所提及的错误。请找到以下代码

  createReportFormulaInfo(): Array<ReportFormulaEntity> {
    debugger;
    for (let sta in this.selectedSources) {
      debugger;
      let ido = this.selectedSource[sta].id;
      this.selectedFormulaList.push({
        Market_OV: this.selectedSources[sta].Market,
        Set_Name: this.selectedSources[sta].Value,
        Data_ID: Number(this.selectedSources[sta].Market),
        Set_number: 0,
        Formula_Set1: "",
        Formula_Set2: "",
        Formula_type: "",
        Date_From: "",
        Date_To: "",
        UpdateFlag: "A",
        Is_Current: 0
      });
    }
   }

我不确定如何解决此问题，我正在使用角度4。任何人都可以帮助这个查询。预先感谢。

Answer 1

来自https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in#Array_iteration_and_for...in

注意：for ... in不应用于遍历其中索引顺序很重要。

您将基于局部变量进行迭代

 createReportFormulaInfo(): Array<ReportFormulaEntity> {
    debugger;
    for (i=0;i<this.selectedSources.length;i++) {
      debugger;
      let ido = this.selectedSource[i].id;
      this.selectedFormulaList.push({
        Market_OV: this.selectedSources[i].Market,
        Set_Name: this.selectedSources[i].Value,
        Data_ID: Number(this.selectedSources[i].Market),
        Set_number: 0,
        Formula_Set1: "",
        Formula_Set2: "",
        Formula_type: "",
        Date_From: "",
        Date_To: "",
        UpdateFlag: "A",
        Is_Current: 0
      });
    }
   }

另一种方法是使用数组的foreach方法

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach

在角度循环遍历数组时无法读取未定义的0属性

1 个答案: