function more(arr) {
let max=null;//定义一个用来存储出现次数最多的元素
let num=1;//定义一个用来存储最出现的次数
arr.reduce((p,k)=>{
//对该数组进行reduce遍历
p[k]?p[k]++:p[k]=1;
if(p[k]>num){
num=p[k]
max=k
}
return p
},{
})
return {
max:max,num:num}//返回最多元素对象
}
The idea of this method is to convert the entire array into a pseudo-array object: the elements and the number of occurrences are stored as key-value pairs.
The second argument to reduce is the initial value passed to the function, and the first argument is a function. Then {} is passed to the p parameter for the first time in this method, and the k parameter is the currently traversed object, which is equivalent to the item parameter in Foreach.