索引巢狀 JSON 數組

Question

我有以下 JSON 範例，其中 "results" 下有一個數組，其中包含兩個物件。它可以在 “results” 陣列下包含數百個具有相同鍵和不同值的物件。

我無權更改此 JSON 檔案。

{
  "results": [
    {
      "title": "Information Collection Requests; Direct Loan Servicing-Regular; and Servicing Minor Program Loans",
      "type": "Notice",
      "abstract": "In accordance with the Paperwork Reduction Act (PRA) requirement, the Farm Service Agency (FSA) is requesting comments from all interested individuals and organizations on a revision of two currently approved information collection requests, Direct Loan Servicing--Regular and Servicing Minor Program Loans, respectively. In the Direct Loan Servicing--Regular, the information is used to determine borrower compliance with loan agreements, assist the borrower in achieving business goals, and regular servicing of the loan account such as graduation, subordination, partial release, use of proceeds, and consent. In Servicing Minor Program Loans, the information collected is used to perform routine and special servicing actions for loans authorized and serviced under FSA's Minor Loan Program.",
      "document_number": "2023-05464",
      "html_url": "https://www.federalregister.gov/documents/2023/03/17/2023-05464/information-collection-requests-direct-loan-servicing-regular-and-servicing-minor-program-loans",
      "pdf_url": "https://www.govinfo.gov/content/pkg/FR-2023-03-17/pdf/2023-05464.pdf",
      "public_inspection_pdf_url": "https://public-inspection.federalregister.gov/2023-05464.pdf?1678970722",
      "publication_date": "2023-03-17",
      "agencies": [
        {
          "raw_name": "DEPARTMENT OF AGRICULTURE",
          "name": "Agriculture Department",
          "id": 12,
          "url": "https://www.federalregister.gov/agencies/agriculture-department",
          "json_url": "https://www.federalregister.gov/api/v1/agencies/12",
          "parent_id": null,
          "slug": "agriculture-department"
        },
        {
          "raw_name": "Farm Service Agency",
          "name": "Farm Service Agency",
          "id": 157,
          "url": "https://www.federalregister.gov/agencies/farm-service-agency",
          "json_url": "https://www.federalregister.gov/api/v1/agencies/157",
          "parent_id": 12,
          "slug": "farm-service-agency"
        }
      ],
      "excerpts": "In accordance with the Paperwork Reduction Act (PRA) requirement, the Farm Service Agency (FSA) is requesting comments from all interested individuals and organizations on a revision of two currently approved information collection requests, Direct..."
    },
    {
      "title": "Notice of Funding Opportunity for the Socially Disadvantaged Groups Grant for Fiscal Year 2023",
      "type": "Notice",
      "abstract": "This notice announces that the Rural Business-Cooperative Service (RBCS, Agency), a Rural Development (RD) agency of the United States Department of Agriculture (USDA), invites applications for grants under the Socially Disadvantaged Groups Grant (SDGG) program for Fiscal Year (FY) 2023. This notice is being issued to allow applicants sufficient time to leverage financing, prepare and submit their applications, and give the Agency time to process applications within FY 2023. A total of ,000,000 in grant funding will be available for FY 2023. Successful applications will be selected by the Agency for funding and subsequently awarded to the extent that funding may ultimately be made available through appropriations. All applicants are responsible for any expenses incurred in developing and submitting their applications.",
      "document_number": "2023-05441",
      "html_url": "https://www.federalregister.gov/documents/2023/03/17/2023-05441/notice-of-funding-opportunity-for-the-socially-disadvantaged-groups-grant-for-fiscal-year-2023",
      "pdf_url": "https://www.govinfo.gov/content/pkg/FR-2023-03-17/pdf/2023-05441.pdf",
      "public_inspection_pdf_url": "https://public-inspection.federalregister.gov/2023-05441.pdf?1678970718",
      "publication_date": "2023-03-17",
      "agencies": [
        {
          "raw_name": "DEPARTMENT OF AGRICULTURE",
          "name": "Agriculture Department",
          "id": 12,
          "url": "https://www.federalregister.gov/agencies/agriculture-department",
          "json_url": "https://www.federalregister.gov/api/v1/agencies/12",
          "parent_id": null,
          "slug": "agriculture-department"
        },
        {
          "raw_name": "Rural Business-Cooperative Service",
          "name": "Rural Business-Cooperative Service",
          "id": 456,
          "url": "https://www.federalregister.gov/agencies/rural-business-cooperative-service",
          "json_url": "https://www.federalregister.gov/api/v1/agencies/456",
          "parent_id": 12,
          "slug": "rural-business-cooperative-service"
        }
      ],
      "excerpts": "This notice announces that the Rural Business-Cooperative Service (RBCS, Agency), a Rural Development (RD) agency of the United States Department of Agriculture (USDA), invites applications for grants under the Socially Disadvantaged Groups Grant..."
    }
  ]
}

我有以下程式碼來取得並顯示數組中每個鍵所需的值，如下所示：

const xmlhttp = new XMLHttpRequest();
xmlhttp.onload = function() {
  const myArr = JSON.parse(this.responseText);

  let text = "";
  for (let i in myArr.results) {
    text += "<div class='fed-reg-container'><h2 class='title'>" + myArr.results[i].title + "</h2><p>" + myArr.results[i].type + "</p><p>" + myArr.results[i].agencies[0].raw_name + " Document # " + myArr.results[i].document_number + "</p><p>Posted on: " + myArr.results[i].publication_date + "</p><p>" + myArr.results[i].abstract + "</p><a class='fed-reg-button' href='" + myArr.results[i].html_url + "'>Read More</a></div>";
  }
  text += "";
  document.getElementById("demo").innerHTML = text;
};
xmlhttp.open(
  "GET",
  "https://www.federalregister.gov/api/v1/documents.json?conditions%5Bagencies%5D%5B%5D=agriculture-department&conditions%5Bagencies%5D%5B%5D=federal-highway-administration&conditions%5Bagencies%5D%5B%5D=fish-and-wildlife-service&conditions%5Bagencies%5D%5B%5D=forest-service&conditions%5Bagencies%5D%5B%5D=interior-department&conditions%5Bagencies%5D%5B%5D=international-boundary-and-water-commission-united-states-and-mexico&conditions%5Bagencies%5D%5B%5D=land-management-bureau&conditions%5Bagencies%5D%5B%5D=national-highway-traffic-safety-administration&conditions%5Bagencies%5D%5B%5D=national-park-service&conditions%5Bagencies%5D%5B%5D=reclamation-bureau&conditions%5Bagencies%5D%5B%5D=environmental-protection-agency&conditions%5Bagencies%5D%5B%5D=council-on-environmental-quality&conditions%5Bagencies%5D%5B%5D=safety-and-environmental-enforcement-bureau&conditions%5Bagencies%5D%5B%5D=environment-office-energy-department&conditions%5Bcomment_date%5D%5Bgte%5D=05%2F01%2F2023&conditions%5Bcomment_date%5D%5Blte%5D=01%2F01%2F2050&conditions%5Bterm%5D=arizona&conditions%5Btype%5D%5B%5D=RULE&conditions%5Btype%5D%5B%5D=PRORULE&conditions%5Btype%5D%5B%5D=NOTICE",
  true
);
xmlhttp.send();

.fed-reg-container {
  background-color: black;
  color: white;
  padding: 20px;
  margin: 20px 0;
}

.title {
  color: #fcb900;
}

.fed-reg-button {
  background-color: #fcb900;
  color: black;
  padding: 10px;
  display: block;
  max-width: 100px;
  text-align: center;
  font-weight: 600;
  text-decoration: none;
}

<!DOCTYPE html>
<html>

<body>
  <p id="demo"></p>

</body>

</html>

一切都很好，除了一件事。

如您所見，我的 json 在 "agencies" 下有一個巢狀數組，其中包含多個物件。

我正在嘗試使用索引來獲取每個物件的 raw_name 下的每個值。

如果我使用 myArr.results[i].agencies[0].raw_name 它適用於單一物件。可能是 [0] 或 [1]。

當我嘗試取得第二個值（例如 myArr.results[i].agencies[0].raw_name " - " myArr.results[i].agencies[1].raw_name 時，它會破壞整個程式碼。我沒有得到任何回報。只是一個白頁。

知道我做錯了什麼嗎？

謝謝！

Answer 1

使用巢狀循環來處理所有機構。您可以使用 map() 循環它們並傳回名稱數組，並使用 join() 將它們與分隔符號連接起來。

for (let i in myArr.results) {
    let agencies = myArr.results[i].agencies.map(a => a.raw_name).join(', ');
    text += "
" + myArr.results[i].title + "
" + myArr.results[i].type + "
" + agencies + " Document # " + myArr.results[i].document_number + "
Posted on: " + myArr.results[i].publication_date + "
" + myArr.results[i].abstract + "
Read More
";
  }