数组里的字符串转换成数字或者把数字转换成字符串

数组里的字符串转换成数字或者把数字转换成字符串

var arr1 = [1, 2, 3, 4, 5, 6, 7, 8, 9];
arr1.map(String);  //结果： ['1', '2', '3', '4', '5', '6', '7', '8', '9']

var arr2 = ['1', '2', '3', '4', '5', '6', '7', '8', '9']
arr2.map(Number);  //结果：[1, 2, 3, 4, 5, 6, 7, 8, 9]