object array Group by an element?

Question

Please see this example: JsFiddle

Question: I have the following JSON Array

y= [ {\"LngTrend\":15,\"DblValue\":10,\"DtmStamp\":13582260         


        

Answer 1

 var y = [
   {"LngTrend":15,"DblValue":10,"DtmStamp":1358226000000},     
   {"LngTrend":16,"DblValue":92,"DtmStamp":1358226000000},    
   {"LngTrend":17,"DblValue":45,"DtmStamp":1358226000000},
   {"LngTrend":18,"DblValue":87,"DtmStamp":1358226000000},
   {"LngTrend":15,"DblValue":10,"DtmStamp":1358226060000},
   {"LngTrend":16,"DblValue":87,"DtmStamp":1358226060000},
   {"LngTrend":17,"DblValue":45,"DtmStamp":1358226060000},
   {"LngTrend":18,"DblValue":92,"DtmStamp":1358226060000},
 ];
var x = {};

for(var k in y){
  if(x[y[k]["DtmStamp"]] == undefined)
     x[y[k]["DtmStamp"]] = [];
     x[y[k]["DtmStamp"]].push(y[k]["DblValue"])
}
alert(JSON.stringify(x))
console.log(x);

See http://plnkr.co/edit/511sKSdzHGYuvpYqKCPD?p=preview