JS 将数字字符串数组转为 数字数组 （互换）
var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9]; arr.map(String); //结果： ['1', '2', '3', '4', '5', '6', '7', '8', '9'] var a = ['1', '2', '3', '4', '5', '6', '7', '8', '9'] a.map(Number); //结果：[1, 2, 3, 4, 5, 6, 7, 8, 9]
var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9]; arr.map(String); //结果： ['1', '2', '3', '4', '5', '6', '7', '8', '9'] var a = ['1', '2', '3', '4', '5', '6', '7', '8', '9'] a.map(Number); //结果：[1, 2, 3, 4, 5, 6, 7, 8, 9]
