CODEWITHSUNDEEP
javascriptarraysjson
Motombo
Motombo

Reputation: 1787

Getting JSON values by order and keeping the corresponding names in order

I currently have some JSON data like the following:

{"data": [
    {"student_id": "bobby", "solved": 19},
    {"student_id": "smith", "solved": 20}
]}

Now what I am doing right now is pushing the solved values into an array called newData in a for loop like the following:

newData.push(data['data'][i].solved);

Now I sort these by values by using this function:

newData.sort(function(a,b){
    return a-b;        
});

Great, now I have an array of values in order. But how can I retrieve the names which correspond to these values which I sorted in order? It would be nice if I could have the names and solved in two arrays, but each index corresponds to the same in the original JSON data. One huge array with objects and values sorted is ok too I guess.

Upvotes: 2

Views: 67

Answers (5)

cstuncsik
cstuncsik

Reputation: 2796

With small reusable one-liners

const {data} = {"data": [
    {"student_id": "bobby", "solved": 19},
    {"student_id": "smith", "solved": 20}
]};

const sortBy = (by,arr) => arr.slice().sort((a,b) => b[by] - a[by]);
const getProp = (prop,obj) => obj[prop];

const sortById = sortBy.bind(null, 'student_id');
const sortBySolved = sortBy.bind(null, 'solved');

const getId = getProp.bind(null, 'student_id');
const getSolved = getProp.bind(null, 'solved');

const sortedIds = sortById(data).map(getId);
const sortedSolutions = sortBySolved(data).map(getSolved);

console.log(sortedIds);
console.log(sortedSolutions);

Upvotes: 1

Nenad Vracar
Nenad Vracar

Reputation: 122087

You can first sort data by solved key and then use map() to return two separate arrays of results in sorted order.

var obj = {"data": [{"student_id": "bobby", "solved": 19}, {"student_id": "smith", "solved": 20}]}

var newData = obj.data.sort(function(a, b) {
  return b.solved - a.solved;
});

var numbers = newData.map(e => e.solved);
var names =  newData.map(e => e.student_id);

console.log(numbers);
console.log(names);

Upvotes: 2

Patrick Barr
Patrick Barr

Reputation: 1123

To keep all the data sorted and kept in a single array, you could create an object and put that into the array by doing something like this in the for loop:

    newData.push({
        student_id: data['data'][i].student_id,
        solved: data['data'][i].solved
    });

And when you go to sort it, you just need to change the sort function to do:

    newData.sort(function(a,b){
        return a.solved - b.solved;        
    });

When you go to access the array later instead of using, for example, newData[3], just change the line to newData[3].solved or newData[3]['solved'].

Keeping your data in a single array like this will help make it easier to keep your student_id and solved values paired with each other. When you use multiple arrays, it is easier to have your indices mismatch with each other. But there's nothing stopping you from using more than one.

Upvotes: 1

zeppelin
zeppelin

Reputation: 9365

You can also use "lodash" or "underscore" to sort your data by "solved", in just one line of code:

var data = {"data": [{"student_id": "bobby", "solved": 19}, {"student_id": "smith", "solved": 20}]}
var sorted = _.sortBy(data["data"],['solved']);

see https://lodash.com/docs#sortBy

Upvotes: 1

Blue
Blue

Reputation: 22911

Why don't you just sort the actual objects?

json.data.sort(function(a, b) {
    return a.solved - b.solved;        
});

Now you have a sorted array of objects. If you want the lowest student, just use sorted[0].student_id. You can see how this works below:

var obj = {"data": [{"student_id": "bobby", "solved": 19}, {"student_id": "smith", "solved": 18}]};
             
console.log('Raw Data: ', obj.data);

var sorted = obj.data.sort(function(a,b){
    return a.solved-b.solved;
    });

console.log('Sorted: ', sorted);

Upvotes: 1

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