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));