js-1

数组操作

this.arr.push('tzh','zmr');
this.arr.pop();
this.arr.shift();//删除开头的元素
this.arr.unshift('tzh','zmr');//在开头添加元素
this.arr.splice(2);//删除下标2以及之后的元素
this.arr.splice(2,2);//删除下标从2开始的2个元素
this.arr.splice(2,0,'lhy');//在下标为2的后面插入一个‘lhy’
this.arr.splice(2,2,'lhy','zt');//从下标2开始的2个元素替换为'lhy' 'zt'
Vue.set(this.arr,0,'sxy');


var animals = [
  {name: 'Fluffykins', species: 'rabbit'},
  {name: 'Caro', species: 'dog'},
  {name: 'Hamilton', species: 'dog'},
  {name: 'harold', species: 'fish'}
]
//回调函数执行arr.length次
//过滤
var newArr = arr.filter(function(x){
  return x === 'dog'
})
//映射
var names = arr.map(function(x){
  return x*x
})
//求和
arr.reduce(function(preVal,x){
  return preVal + x
},0)

 

    var animals = [

      {name: 'Fluffykins', species: 'rabbit'},

      {name: 'Caro', species: 'dog'},

      {name: 'Hamilton', species: 'dog'},

      {name: 'harold', species: 'fish'}

    ]

    var isDog = function(animal){

      return animal.species === 'dog'

    }

    var dogs = animals.filter(isDog)

    var otherAnimals = animals.reject(isDog)