var arr = ['A','B','4','C','1','D','7','8', '9'];
arr.sort();
var num_set = [],
? str_set = [];
for (var i = 0; i < arr.length; i ++) {
? if (arr[i].charCodeAt(0) < 65) {
? ? ?num_set.push(arr[i]);
? } else {
? ? ?str_set.push(arr[i]);
? }
}
console.log(num_set);
console.log(str_set);
var ret = [];
for (var i = 0, j = 0; i < num_set.length, j < str_set.length; i ++, j ++) {
? ret.push(str_set[j] + num_set[i]);
}
console.log(ret);

沒有直接排序法，有間接排序法。