jQuery的多级JSON

Question

I am trying to create some json that is a few levels deep, and I am having trouble in 2 places. The first, is getting the format correct. I also want to add a "level_two" to the data set.

The second is parsing the data. Any help would be greatly appreciated.

Thanks!

JSON:
{
    "math_problems": [
        {
            "level_one": {
                "addition": {
                   "problem": {
                        "data_set": [
                            3,
                            2
                        ]
                    },
                    "problem": {
                        "data_set": [
                            5,
                            1
                        ]
                    }
                },
                "subtraction": {
                    "problem": {
                        "data_set": [
                            4,
                            2
                        ]
                    }
                },
                "division": {
                    "problem": {
                        "data_set": [
                            3,
                            2
                        ]
                    }
                },
                "multiplication": {
                    "problem": {
                        "data_set": [
                            3,
                            2
                        ]
                    }
                }
            }
        }
    ]
}


jQuery:

$.getJSON('/data/math.json', function(data) {

        var the_data = [];

        $.each(data,function(index,item) {
            i = index;
            number_one = item[0]['level_one']['addition']['problem']['data_set'][0];
            number_two = item[0]['level_one']['addition']['problem']['data_set'][1];

            the_data += number_one + " + " + number_two;
        });

        $('<ul/>', {
            'class': 'my-new-list',
            html: the_data + " = " + (number_one + number_two)
        }).appendTo('body');
    });

I want to be able to parse the data to pull out say:

level_one > addition > problem 1 > 3, 2

level_two > subtraction > problem 1 > 4, 3

Any ideas?

Answer 1

The problem is, you have the same key defined in a hash at the same level:

"problem": {
    "data_set": [
        3,
        2
    ]
},
"problem": {
    "data_set": [
        5,
        1
    ]
}

These will collide and overwrite each other. Restructure it to be an array, and you should be good.

Answer 2

So the correct JSON is:

var object = {
    levelOne: {
        // etc.
    },
    levelTwo: {
        // etc.
    }
}

Parsing it is done using JSON.parse() and then traversing it is like:

object.level_one.prop.prop1;
object.level_two.otherProp.otherProp2;

Answer 3

JSON gets converted into a javascript object, so the fact that you repeat the key "problem" on the "addition" makes the second "problem" overwrite the first.

You should rethink your json structure, maybe something like:

"math_problems" : {
  "level_one": {
    "addition": {
      "problems": [
        {
          "data_set": [3,2]
        },
        {
          "data_set": [5,1]
        }
      ]
    },
    "subtraction": ...     
  }  
}

or, in case the problems, problem types and levels are highly dynamic:

"math_problems" : {    
  "levels": [
    {
      "name" : "Level one",
      "problems": [
        {
          "type" : "addition",
          "data_set": [3,2]
        },
        {
          "type" : "addition",
          "data_set": [5,1]
        },
        {
          "type" : "subtraction",
          "data_set": [2,1]
        }
      ]
    },
    {
      "name" : "Level two",
      "problems": [
        ...
      ]
    }
  ]
}