javascript分组（还算高效）

var arr =  [        ['aaa',1,2,3],        ['bbb',2,4,'c'],        ['ccc',2,35,6],        ['aaa',45,14,78],        ['bbb',77,74,11],        ['aaa',14,1425,14],        ['ccc',14,14,18]      ];var gro = {};for(var i=0;i<arr.length;i++){if(gro[arr[i][0]]){gro[arr[i][0]].push(arr[i]);}else{gro[arr[i][0]] = [];gro[arr[i][0]].push(arr[i]);}}alert(JSON.stringify(gro));