(1)依据数组对象中某个值,将相同的对象合并成一个新对象
数据源是这样的
beforeData: [
{ name: "tony", id: "1", age: "20" },
{ name: "jack", id: "2", age: "21" },
{ name: "tony", id: "3", age: "50" },
{ name: "jack", id: "4", age: "10" },
{ name: "mark", id: "5", age: "22" },
{ name: "mark", id: "6", age: "40" }
]
要将数据中name相同的项合并成一个对象
afterData: [
{name: "tony",origin: [{ name: "tony", id: "1", age: "20" },{ name: "tony", id: "3", age: "50" }]},
{name: "jack",origin: [{ name: "jack", id: "2", age: "21" },{ name: "jack", id: "4", age: "10" }]},
{name: "mark",origin: [{ name: "mark", id: "5", age: "22" },{ name: "mark", id: "6", age: "40" }]}
]
实现:
let tempArr = [];
for (let i = 0; i < this.beforeData.length; i++) {
if (tempArr.indexOf(this.beforeData[i].name) === -1) {
this.afterData.push({
name: this.beforeData[i].name,
origin: [this.beforeData[i]]
});
tempArr.push(this.beforeData[i].name);
} else {
for (let j = 0; j < this.afterData.length; j++) {
if (this.afterData[j].name == this.beforeData[i].name) {
this.afterData[j].origin.push(this.beforeData[i]);
break;
}
}
}
}
(2)根据数组中对象的某一个属性值进行排序
如下代码,根据数组对象中的age进行排序
方式一:
var arr = [
{name:'zopp',age:0},
{name:'gpp',age:18},
{name:'yjj',age:8}
];
function compare(property){
return function(a,b){
var value1 = a[property];
var value2 = b[property];
return value1 - value2;
}
}
console.log(arr.sort(compare('age')))
方式二:
students:[
{name:'baibai',age:32},
{name:'xiaobai',age:30},
{name:'gufan',age:21},
{name:'King',age:45}
]
//数组对象方法排序:
function sortByKey(array, key) {
return array.sort(function(a, b) {
var x = a[key];
var y = b[key];
return ((x < y) ? -1 : ((x > y) ? 1 : 0));
})
}
//将相应的数组对象传入即可完成排序:
sortByKey(students,age);
(3)数组的值大小排序
如下代码,将数组中的值进行大小排序
let values = [1,2,3,6,4,8];
//小到大排序,如果需要由大到小,把返回的-1和1反过来就可以了
let compare = (x,y) => {
if(x < y){
return -1
}else if(x > y){
return 1;
}else{
return 0;
}
}
console.log(values.sort(compare)); //[1, 2, 3, 4, 6, 8]
(4)数组中相同元素组合成一个新的数组
现在有一个这样规律的数组,需求是把里面相同元素组合成一个新的数组;
arr=['1','1','1','2',,'3','4','5','5','6','6','7','8','9','9','10']
结果是这样的
newArr = [ [ "1" , "1" , "1" ] , [ "2" ] , [] , [ "3" ] , [ "4" ] , [ "5" , "5" ] , [ "6" , "6" ] , [ "7" ] , [ "8" ] , [ "9" , "9" ] , [ "10" ] ]
实现方式:
var arr=['1','1','1','2',,'3','4','5','5','6','6','7', '8','9','9','10'];
var newArr = [],
tempArr = [];
for(var i=0,j=arr.length;i<j;i++){
if(arr[i] == arr[i+1]){
tempArr.push(arr[i]);
} else {
tempArr.push(arr[i]);
newArr.push(tempArr.slice(0));
tempArr.length = 0;
}
}
console.log(newArr);
/*[ [ "1" , "1" , "1" ] , [ "2" ] , [] , [ "3" ] , [ "4" ] ,[ "5" , "5" ] , [ "6" , "6" ] , [ "7" ] , [ "8" ] , [ "9" , "9" ] , [ "10" ] ]*/