Question

我正在尝试显示我的数组的内容但是存在重复的地方只是打印名称和数字，例如

myArr = ['apple', 'apple', 'orange', 'apple', 'banana', 'orange', 'pineapple']

会显示;

apple 3
orange 2
banana
pineapple

到目前为止，我将它们全部作为字符串返回：

arrList = myArr.join(', ');
arrList.toString()

Answer 1

很长的路

var elements = ["apple", "apple", "orange", "apple", "banana"];

elements.sort();

var current = null;
var count = 0;

for(var i = 0; i < elements.length; i++)
{
    if(elements[i] != current)
  {
    if(count > 0)
    {
        document.write(current + " " + count + "<br/>");
    }
    current = elements[i];
    count = 1;
  }
  else
  {
    count++;
  }
}

if(count > 0)
{
    document.write(current + " " + count);

简短

var elements = ["apple", "apple", "orange", "apple", "banana"];

var counts = {};

elements.forEach(function(x) {
    counts[x] = (counts[x] || 0) + 1;
});

document.write("Apple: " + counts.apple + "<br/>");
document.write("Banana: " + counts.banana + "<br/>");
document.write("Orange: " + counts.orange + "<br/>");

Answer 2

试试这个：

＆＃13;

var myArr = ['apple', 'apple', 'orange', 'apple', 'banana', 'orange', 'pineapple'];
var obj = {};
myArr.forEach(function(item) {
  if (typeof obj[item] == 'number') {
    obj[item]++;
  } else {
    obj[item] = 1;
  }
});
document.getElementById('output').innerHTML = Object.keys(obj).map(function(item) {
  return item + (obj[item] == 1 ? '' : ' ' + obj[item]);
}).join('\n');

＆＃13;

<pre id="output"></pre>

＆＃13;

计算数组中的重复项

2 个答案: