Question

我有如下的Json Array。

{  
   "leader_lessons":{  
      "lessons":{  
         "class_sec_data":{  
            "1":{  
               "leader_id":"1111",
               "leader_school":null,
               "leader_std":"Std2",
               "leader_section":"B",
               "leader_lesson_date":"2018-12-09",
               "school_lesson_code":"Std2.2",
               "leader_lessonName":"SUM - Mathematics"
            },
            "2":{  
               "leader_id":"1111",
               "leader_school":null,
               "leader_std":"Std2",
               "leader_section":"D",
               "leader_lesson_date":"2018-12-09",
               "school_lesson_code":"Std2.2",
               "leader_lessonName":"SUM - Mathematics"
            },
            "3":{  
               "leader_id":"1111",
               "leader_school":null,
               "leader_std":"UKG",
               "leader_section":"C",
               "leader_lesson_date":"2018-12-09",
               "school_lesson_code":"UKG.31",
               "leader_lessonName":"Rhymes English"
            },
            "4":{  
               "leader_id":"1111",
               "leader_school":null,
               "leader_std":"UKG",
               "leader_section":"D",
               "leader_lesson_date":"2018-12-09",
               "school_lesson_code":"UKG.31",
               "leader_lessonName":"Rhymes English"
            },
            "5":{  
               "leader_id":"1111",
               "leader_school":null,
               "leader_std":"UKG",
               "leader_section":"H",
               "leader_lesson_date":"2018-12-09",
               "school_lesson_code":"UKG.31",
               "leader_lessonName":"Rhymes English"
            },
            "6":{  
               "leader_id":"1111",
               "leader_school":null,
               "leader_std":"UKG",
               "leader_section":"G",
               "leader_lesson_date":"2018-12-09",
               "school_lesson_code":"UKG.31",
               "leader_lessonName":"Rhymes English"
            }
         }
      },
      "dates":[  
         "2018-12-09",
         "2018-12-09"
      ]
   }
}

我必须计算class_sec_data的长度，并且在迭代i中必须分配给HTML标记，如下所示。

for(var i = 0; i < school_leader_json.leader_lessons.lessons.class_sec_data.length; i++)
{

  counter= counter+1;
  $setInnerControlHTML("LD_Class_"+counter, school_leader_json.leader_lessons.lessons.class_sec_data[counter].leader_std);
  $setInnerControlHTML("LD_Section_"+counter, school_leader_json.leader_lessons.lessons.class_sec_data[counter].leader_section);
  $setInnerControlHTML("LD_Lesson_"+counter, school_leader_json.leader_lessons.lessons.class_sec_data[counter].leader_lessonName);

}

但是school_leader_json.leader_lessons.lessons.class_sec_data.length是未定义的。

Answer 1

您正在循环对象而不是数组。

一个数组看起来像这样：

let myArray = [];

一个对象看起来像这样：

let myObject = {};

将对象视为关联数组，即键->值对的列表。这些键称为对象属性。在您的情况下，键为“ 1”，“ 2”等。

const school_leader_json = {"leader_lessons":{"lessons":{"class_sec_data":{"1":{"leader_id":"1111","leader_school":null,"leader_std":"Std2","leader_section":"B","leader_lesson_date":"2018-12-09","school_lesson_code":"Std2.2","leader_lessonName":"SUM - Mathematics"},"2":{"leader_id":"1111","leader_school":null,"leader_std":"Std2","leader_section":"D","leader_lesson_date":"2018-12-09","school_lesson_code":"Std2.2","leader_lessonName":"SUM - Mathematics"},"3":{"leader_id":"1111","leader_school":null,"leader_std":"UKG","leader_section":"C","leader_lesson_date":"2018-12-09","school_lesson_code":"UKG.31","leader_lessonName":"Rhymes English"},"4":{"leader_id":"1111","leader_school":null,"leader_std":"UKG","leader_section":"D","leader_lesson_date":"2018-12-09","school_lesson_code":"UKG.31","leader_lessonName":"Rhymes English"},"5":{"leader_id":"1111","leader_school":null,"leader_std":"UKG","leader_section":"H","leader_lesson_date":"2018-12-09","school_lesson_code":"UKG.31","leader_lessonName":"Rhymes English"},"6":{"leader_id":"1111","leader_school":null,"leader_std":"UKG","leader_section":"G","leader_lesson_date":"2018-12-09","school_lesson_code":"UKG.31","leader_lessonName":"Rhymes English"}}},"dates":["2018-12-09","2018-12-09"]}};

const class_sec_data = school_leader_json.leader_lessons.lessons.class_sec_data;

let counter = 0;
for(let key in class_sec_data){
  console.log(class_sec_data[key]);
  
    counter++;
    
  // $setInnerControlHTML("LD_Class_"+counter, class_sec_data[key].leader_std);
  // $setInnerControlHTML("LD_Section_"+counter, class_sec_data[key].leader_section);
  // $setInnerControlHTML("LD_Lesson_"+counter, class_sec_data[key].leader_lessonName);
}

console.log('Total:', counter);

Answer 2

如下所示。

const class_sec_data = school_leader_json.leader_lessons.lessons.class_sec_data;

let counter = 0;
for(let key in class_sec_data){
  console.log(class_sec_data[key]);

    counter++;


    $setControlInnerHTML("LD_Class_"+key, school_leader_json.leader_lessons.lessons.class_sec_data[key].leader_std);
    $setControlInnerHTML("LD_Section_"+key, school_leader_json.leader_lessons.lessons.class_sec_data[key].leader_section);
    $setControlInnerHTML("LD_Lesson_"+key, school_leader_json.leader_lessons.lessons.class_sec_data[key].leader_lessonName);
}

Json Array中的数组计数和解析

2 个答案: