json格式数据的添加，删除及排序方法

var a = ['1'];a[5] = 52;a.length //这儿的结果是6，也就是说，中间的key会自动补全，而值呢，是undefined

test = {}; //空json对像test['firstname'] = "tank"; //添加二个元素test['lastname'] = "zhang";console.log(test); //查看delete test['lastname']; //删除json中的某个元素console.log(test);

test1 = [{"name":"tank","total":"100"},{"name":"zhang","total":"23"},{"name":"hao","total":"325"}];add = {"name":"may"};test1.push(add); //添加一个元素console.log(test1);delete test1[2]; //删除一个元素console.log(test1);

test = ["100","23","325"]; //定义个数组function sortNumber(a,b) //定义排序方法{   return a - b}test1_sort=test.sort(sortNumber);console.log(test1_sort);

test1 = [{"name":"tank","total":"100"},{"name":"zhang","total":"23"},{"name":"hao","total":"325"}];sort_by = function(field, reverse, primer){ //定义排序方法  var key = primer ?    function(x) {return primer(x[field])} :    function(x) {return x[field]};  reverse = [-1, 1][+!!reverse];  return function (a, b) {    return a = key(a), b = key(b), reverse * ((a > b) - (b > a));   }}test1_sort=test1.sort(sort_by('total', true, parseInt)); //根据total，升序排console.log(test1_sort);test1_sort=test1.sort(sort_by('name', false, '')); //根据name，倒序排console.log(test1_sort);