根据 JavaScript/jQuery 中的计数将数组转换为子数组？ [关闭]

Question

如何根据 JavaScript 或 jQuery 中的元素值计数将我的数组转换为子数组？

例如：

var myArray=["a","b","c","a","a","c","b"];

计算元素 a、b 和 c 后的预期输出

outputArray=[["a",3],["b",2],["c",2]];

Answer 1

您可以使用 reduce() 和 ES6 Map() 并传播语法 ...。

var myArray=["a","b","c","a","a","c","b"];

var result = [...myArray.reduce(function(r, e) {
  return r.set(e, !r.get(e) ? 1 : r.get(e) + 1)
}, new Map())]

console.log(result)

Answer 2

如果你想以自己的方式解决问题，那就试试吧

var myArray=["a","b","c","a","a","c","b"];
var obj = [];
for (var i = 0, j = myArray.length; i < j; i++) {
   obj[myArray[i]] = (obj[myArray[i]] || 0) + 1;
}
var finalArr = [];
for (var key in obj) {
    if (obj.hasOwnProperty(key)) {
        var arr = [];
        arr.push(key);
        arr.push(obj[key]);
        finalArr.push(arr);
    }
}
console.log(finalArr);

Answer 3

function countLetters(arr) {
    return arr.reduce(function(r, e) {
        r[e] = (r[e] || 0) + 1;
        return r;
    }, {});
}

另一种方法