如何在javascript中计算数组中的重复值

javascript arrays

2022-08-30 02:26:46

目前，我得到了一个这样的数组：

var uniqueCount = Array();

几个步骤后，我的数组看起来像这样：

uniqueCount = [a,b,c,d,d,e,a,b,c,f,g,h,h,h,e,a];

如何计算数组中有多少 a，b，c？我想要一个这样的结果：

a = 3
b = 1
c = 2
d = 2

等。

答案 1

const counts = {};
const sampleArray = ['a', 'a', 'b', 'c'];
sampleArray.forEach(function (x) { counts[x] = (counts[x] || 0) + 1; });
console.log(counts)

答案 2

像这样：

uniqueCount = ["a","b","c","d","d","e","a","b","c","f","g","h","h","h","e","a"];
var count = {};
uniqueCount.forEach(function(i) { count[i] = (count[i]||0) + 1;});
console.log(count);

使用简单的for循环而不是forEach，如果你不希望这在较旧的浏览器中中断。