将 JSON 数组转换为对象

Question

I have the following JSON array:

[
    {"id": "01", "state": "Alabama", "category": "Coal", "detail1": null, "detail2": null},
    {"id": "02", "state": "Alaska", "category": null, "detail1": null, "detail2": null},
    {"id": "04", "state": "Arizona", "category": "Oil", "detail1": null, "detail2": null}
]

That I need to turn into this:

{
    "01": { "state":"Alabama", "category":"A", "detail1":"Status 1", "detail2":"Lorem ipsum dolor sit amet, consectetur adipiscing elit. "},
    "02": { "state":"Alaska", "category":"B", "detail1":"Status2", "detail2":"Integer egestas fermentum neque vitae mattis. "},
    "04": { "state":"Arizona", "category":"C", "detail1":"Status 3", "detail2":"Fusce hendrerit ac enim a consequat. "}
}

But I can't figure out how. Can anyone help?

Answer 1

You can loop over the elements, and populate a new Object along the way:

 var arr = [ {"id": "01", "state": "Alabama", "category": "Coal", "detail1": null, "detail2": null}, {"id": "02", "state": "Alaska", "category": null, "detail1": null, "detail2": null}, {"id": "04", "state": "Arizona", "category": "Oil", "detail1": null, "detail2": null} ]; // Here, I create a copy of the array to avoid modifying the original one. var obj = {}, copy = JSON.parse( JSON.stringify(arr) ); for(var i in copy){ obj[ copy[i].id ] = copy[i]; // Add the element to obj, at index id delete copy[i].id; // Remove the id from the inserted object } console.log(obj);

Answer 2

Looping over an array to create a new value typically uses reduce , which allows values to be accumulated in a value that can be passed along to the next invocation of the callback.

I'll assumed in this case that you just want a shallow copy of each member passed in with the id property removed and added to the new value, which can be an object:

 var arr = [ {"id": "01", "state": "Alabama", "category": "Coal", "detail1": null, "detail2": null}, {"id": "02", "state": "Alaska", "category": null, "detail1": null, "detail2": null}, {"id": "04", "state": "Arizona", "category": "Oil", "detail1": null, "detail2": null} ] // Loop over all numeric members of arr var newStructure = arr.reduce(function(obj, v){ // Store the value of the ID property of the passed in object var id = v.id; // Remove the id property from the passed in object delete v.id; // Add the id value and remainder of the object to the accumulator obj[id] = v; // Return the accumulator return obj; },{}); document.write(JSON.stringify(newStructure));

Note that this modifies the original objects, the code to copy them instead isn't much longer.