实战～总结1（hot♨️♨️）

1.将数组中数值元素转为字符串 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']

2.将数组中字符串元素转为数值 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]