如何將for循環中的單獨json對象輸入到數組中？

Question

我正在使用CasperJS抓取網站，其中一項任務涉及通過for循環計數器設置的網址爬行。 網址看起來像這樣

www.example.com/page/no=

其中no是for循環計數器設置的0-10中的任何數字。 然后刮刀遍歷所有頁面，將數據刮入JSON對象並重復直到no = 10。

我想要獲取的數據存儲在每個頁面中的離散組中 - 我想要使用的是通過連接每個頁面的所有刮取輸出的單個JSON對象。

想象一下Page1有Expense 1，我得到的對象是{expense1}，而Page 2有Expense 2，而我得到的對象是{expense2}。 我想要的是在抓取結束時的一個JSON，如下所示：

    scrapedData = {
       "expense1": expense1,
       "expense2": expense2,
     }

我遇到的麻煩是將所有JSON對象加入到一個數組中。

我初始化了一個空數組，然后每個對象都被推送到數組。 我已經嘗試了一個檢查，如果迭代器我在for循環中等於10，那么JSON對象打印出來但似乎沒有用。 我向上看，似乎對象傳播是一個選項，但我不知道如何使用它這種情況。

任何指針都會有所幫助。 我應該使用像map這樣的任何數組函數嗎？

casper.then(function(){    

   var url = "https:example.net/secure/SaFinShow?url=";    
    //We create a for loop to go open the urls

    for (i=0; i<11; i++){

      this.thenOpen(url+ i, function(response){

          expense_amount = this.fetchText("td[headers='amount']");

          Date = this.fetchText("td[headers='Date']");

          Location = this.fetchText("td[headers='zipcode']");

          id = this.fetchText("td[headers='id']");


          singleExpense = {

              "Expense_Amount": expense_amount,
              "Date": Date,
              "Location": Location,
              "id": id
            };

          if (i ===10){
            expenseArray.push(JSON.stringify(singleExpense, null, 2))
            this.echo(expenseArray);
          }
      });

    };
});

Answer 1

以你的榜樣和擴展它為例，你應該能夠做到這樣的事情：

// Initialize empty object to hold all of the expenses
var scrapedData = {};

casper.then(function(){    

   var url = "https:example.net/secure/SaFinShow?url=";    
    //We create a for loop to go open the urls

    for (i=0; i<11; i++){

      this.thenOpen(url+ i, function(response){

          expense_amount = this.fetchText("td[headers='amount']");

          Date = this.fetchText("td[headers='Date']");

          Location = this.fetchText("td[headers='zipcode']");

          id = this.fetchText("td[headers='id']");


          singleExpense = {

              "Expense_Amount": expense_amount,
              "Date": Date,
              "Location": Location,
              "id": id
            };
          // As we loop over each of the expenses add them to the object containing all of them
          scrapedData['expense'+i] = singleExpense;
      });

    };
});

運行后， scrapedData變量應該是以下形式：

scrapedData = {
  "expense1": expense1,
  "expense2": expense2
}

更新的代碼

上面代碼的一個問題是，當你循環開支時，for循環中的變量應該是本地的。 變量名也不應該是Date和Location因為它們是JavaScript中的內置名稱。

// Initialize empty object to hold all of the expenses
var scrapedData = {};

casper.then(function(){    

   var url = "https:example.net/secure/SaFinShow?url=";    
    //We create a for loop to go open the urls

    for (i=0; i<11; i++){

      this.thenOpen(url+ i, function(response){
          // Create our local variables to store data for this particular
          // expense data
          var expense_amount = this.fetchText("td[headers='amount']");

          // Don't use `Date` it is a JS built-in name
          var date = this.fetchText("td[headers='Date']");
          // Don't use `Location` it is a JS built-in name
          var location = this.fetchText("td[headers='zipcode']");

          var id = this.fetchText("td[headers='id']");


          singleExpense = {

              "Expense_Amount": expense_amount,
              "Date": date,
              "Location": location,
              "id": id
            };

          // As we loop over each of the expenses add them to the object containing all of them
          scrapedData['expense'+i] = singleExpense;
      });

    };
});