javascript - 如何计算具有元素值的对象？

Question

我需要你的帮助。我有这样的数组:

  var array = [{
    "name": "Tony",
    "year": "2010"
}, {
    "name": "Helen",
    "year": "2010"
}, {
    "name": "Jack",
    "year": "2005"
}, {
    "name": "Tony",
    "year": "2008"
}, {
    "name": "Max",
    "year": "2005"
}];

我如何按年计算它们并得到这样的结果:

2010 = 2 times;
2005 = 2 times;
2008 = 1 time;

谢谢

Answer 1

检查这个fiddle

var countObj = {};
for( var counter = 0; counter < array.length; counter++ )
{
   var yearValue = array [ counter ].year;
   if ( !countObj[ yearValue ] )
   {
      countObj[ yearValue ] = 0;
   }
   countObj[ yearValue ] ++;
}
console.log( countObj );