数组去重
var count=[1,2,4,5,4,2,4,4,5];
function select (arr){
var arr2=[];
for( var i = 0; i < arr.length; i++){
if (arr2.indexOf(arr[i]) == -1) {
arr2.push(arr[i])
}
}
return arr2;
}
console.log(select(count)); //1245
数组去除对象中重复属性值
var arr = [
{
id: '1',
name: '张三'
},
{
id: '2',
name: '李四'
},
{
id: '1',
name: '王五'
},
{
id: '1',
name: '杨甲'
},
{
id: '2',
name: '白乙'
},
{
id: '3',
name: '孙丁'
}
];
var c=arr.filter(
function(item,index){
var _index=arr.findIndex(
function(_item){
return item.id == _item.id;
});
return index == _index;
});
console.log(c); //arr--3 [{id:'1',name: '张三'},{id:'2',name: '李四'},{id:'3',name: '孙丁'}]
合并数组对象相同的属性值
var arr = [
{ id : 1 , name : '张三'},
{ id : 1 , name : '李四'},
{ id : 3 , name : '王五'},
{ id : 1 , name : '二傻子'},
{ id : 5 , name : '老王'},
{ id : 5 , name : '阿旺'}
];
//按照id相同合并
//
arr=arr.map(function(item,index,arr){
const i=arr.find(_item=>item.id===_item.id);
if(i!==item){
i.name.push(item.name);
return undefined;
}else{
i.name=[i.name];
return i;
}
}).filter(item=>item!==undefined);
console.log(arr);