获取在数组中出现次数最多的项目

Question

var store = ['1','2','2','3','4'];

我想知道2在数组中看起来最多.我该怎么做呢？

Answer 1

我会做的事情如下:

var store = ['1','2','2','3','4'];
var frequency = {};  // array of frequency.
var max = 0;  // holds the max frequency.
var result;   // holds the max frequency element.
for(var v in store) {
        frequency[store[v]]=(frequency[store[v]] || 0)+1; // increment frequency.
        if(frequency[store[v]] > max) { // is this frequency > max so far ?
                max = frequency[store[v]];  // update max.
                result = store[v];          // update result.
        }
}

Answer 2

arr.sort();
    var max=0,result,freq = 0;
    for(var i=0; i < arr.length; i++){
        if(arr[i]===arr[i+1]){
            freq++;
        }
        else {
            freq=0;
        }
        if(freq>max){
            result = arr[i];
            max = freq;
        }
    }
    return result;

Answer 3

解决方案着重于Array.prototype.forEach，如果最大计数多个项目之间共享获得多于一个关键的问题。

编辑：只有一个循环的提案。

var store = ['1', '2', '2', '3', '4', '5', '5'],
    distribution = {},
    max = 0,
    result = [];

store.forEach(function (a) {
    distribution[a] = (distribution[a] || 0) + 1;
    if (distribution[a] > max) {
        max = distribution[a];
        result = [a];
        return;
    }
    if (distribution[a] === max) {
        result.push(a);
    }
});
console.log('max: ' + max);
console.log('key/s with max count: ' + JSON.stringify(result));
console.log(distribution);