Sum of Javascript Object

Question

I have a javascript object in a dictionary that looks like this:

{ date: "2010/01", San_Francisco201001: 1, San_Francisco201002: 2, San_Francisco201003: 3, }, { date: "2010/02", San_Francisco201001: 0, San_Francisco201002: 1, San_Francisco201003: 2, }

And would like to find

{ date: "2010/01", sum: 6, ), { date: "2010/02", sum: 3, )

It gets a bit tricky, because the property names are arbitrary. Any clue how to go about doing this?

Thanks.

Answer 1

That is not one object, that is two objects. I assume that you have them in an array. Then you can loop through the array, and loop through the properties in each object:

var result = [];
for (var i = 0; i < theArray.length; i++) {
  var sum = 0;
  for (var key in theArray[i]) {
    if (key != 'date') {
      sum += theArray[i][key];
    }
  }
  result.push({ date: theArray[i].date, sum: sum });
}

Answer 2

To find the sum of a particular date value, create a function with a body like this:

function getDate(date, arr) {
    for(var i = arr.length; i--;) {
        if(arr[i].date === date) {
            var obj = { sum: 0; };
            for(var prop in arr[i]) {
                if(prop !== "date") {
                    obj.sum += arr[i][prop];
                }
            }
            obj.date = obj.date;
            return obj;
        }
    }
}

Answer 3

This should work:

var data = [{ date: "2010/01", San_Francisco201001: 1, San_Francisco201002: 2, San_Francisco201003: 3, }, { date: "2010/02", San_Francisco201001: 0, San_Francisco201002: 1, San_Francisco201003: 2, }];

var result = [];

for(var i = 0; i < data.length; i++) {
   var dateData = data[i];
   var sum = 0;

   for(var element in dateData) if(dateData.hasOwnProperty(element)) {
      var elementData = dateData[element];

      if(element != "date") {
         sum += elementData;
      }
   }

   result.push({date: dateData["date"], sum: sum});
}

Answer 4

var data = [{ date: "2010/01", San_Francisco201001: 1, San_Francisco201002: 2, San_Francisco201003: 3 }, { date: "2010/02", San_Francisco201001: 0, San_Francisco201002: 1, San_Francisco201003: 2 }];

var out = {};
for(var row in data){

    var stats = data[row];
    var cnt = 0;
    for(var itm in stats){
        if(itm==="date")continue;
        cnt += stats[itm];
    }
    out[stats["date"]] = cnt;
}

alert( out["2010/01"] );