1、filter()
:从数组中筛选出所有满足条件的元素
例如:获取数组中所有性别为女的元素
var arr = [
{id: 1, name: 'Jack', sex: 1},
{id: 2, name: 'Tom', sex: 1},
{id: 3, name: 'Mary', sex: 0},
{id: 4, name: 'Rose', sex: 0},
{id: 5, name: 'Li', sex: 1}
];
var girls = arr.filter(e=>e.sex == 0);
console.log(girls);
//输出结果
[{id: 3, name: 'Mary', sex: 0}, {id: 4, name: 'Rose', sex: 0}]
我们可根据它的特性实现删除数组元素:
例如:删除数组中所有性别为女的元素
var arr = [
{id: 1, name: 'Jack', sex: 1},
{id: 2, name: 'Tom', sex: 1},
{id: 3, name: 'Mary', sex: 0},
{id: 4, name: 'Rose', sex: 0},
{id: 5, name: 'Li', sex: 1}
];
arr = arr.filter(e=>e.sex != 0);
console.log(arr);
//输出结果
[{id: 1, name: 'Jack', sex: 1},
{id: 2, name: 'Tom', sex: 1},
{id: 5, name: 'Li', sex: 1}]
2、map
:从数组中抽取每个元素的指定属性,同java中的keyset()方法:
var rows = [{age:1},{age:2},{age:3},{}];
var ages = rows.map(function (obj) { return obj.age })//结果:[1,2,3,undefined]
3、Math.max.apply
:获取整型数组中的最大值:
var nums = [1,2,3];
var maxNum = Math.max.apply(Math, nums) //结果:3
4、join
数组转字符串:
var ids = [1,2,5,12,9];
var idsStr = ids.join(',');
console.log(idsStr); //结果:1,2,5,12,9
5、split
字符串转数组:
var idsStr = "1,2,5,12,9";
var ids = idsStr.split(',');
console.log(ids); //["1", "2", "5", "12", "9"]
6、concat
连接两个或多个数组:
var arr1 = ['a','b','c'];
var arr2 = ['aa','bb','cc'];
var arr3 = ['1','2','3','a'];
var arr4 = arr1.concat(arr2, arr3);
console.log(arr4);//['a','b','c','aa','bb','cc','1','2','3','a']