输出结果数组,其中包含给定数组的唯一元素的分组计数

Question

如果我有这样的数组,我怎么能循环并将计数推入一个新数组？
所有的帮助都会成功!

    var Products = [
    ['Product A'],
    ['Product A'],
    ['Product A'],
    ['Product A'],
    ['Product A'],
    ['Product B'],
    ['Product B'],
    ['Product B'],
    ['Product B'],
    ['Product B'],
    ['Product B'],
    ['Product B'],
    ['Product B'],    
    ['Product B'],
    ['Old Product B'],
    ['Old Product B'],
    ['Old Product B'],
    ['Old Product B'],
    ['Old Product B'],
    ['Old Product]
         ];

最终目标:

        var UniqueProducts = [
    ['Product A',5],
    ['Product B',6],
    ['Old Product B',9]
     ];

Answer 1

 var obj = {};
 for (var i = 0, l = Products.length; i < l; i++) {
   obj[Products[i][0]] = obj[Products[i][0]] || 0;
   obj[Products[i][0]] += 1;
 }
 console.log(obj);

看到这个小提琴http://jsfiddle.net/XWSRE/1/

但在问这些问题之前,请谷歌一次.这是非常通用的要求,您可以在大多数地方找到解决方案.