使用lodash或下划线js查找数组中字符串元素的出现次数 [英] Find number of occurences of string elements in an Array using lodash or underscore js

问题描述

我有一个以下格式的数组：

I have an array in the following format:

var array = [ 
  { id: '555weibo' },
  { id: '578weibo' },
  { id: '111facebook' },
  { id: '123facebook' },
  { id: '145facebookpage' },
  { id: '145facebookpage' },
  { id: '766facebook' },
  { id: '242facebook' },
  { id: '432twitter' },
  { id: '432exing' }
 ];

我需要找到 facebook ， twitter ， xing ，以及 weibo 里面的那个阵列。
例如：

I need to find the number of occurrences of facebook, twitter, xing, and weibo inside that array. eg:

{
  weibo: 2,
  facebook: 6,
  twitter: 1,
  xing: 1
}

我搜索过一个解决方案，但似乎没有任何工作。

I've searched for a solution, but nothing seems to work.

以下代码未给出预期结果。非常感谢您的帮助。谢谢。

The following code doesn't give the expected result. Your help is much appreciated. Thank you.

var filtered = _.map(diff, function(value, key) {
   return { id: key, count:value };
});

推荐答案

使用下划线：

var services = ['weibo', 'facebook', 'twitter', 'xing'];
var result = _.map(services, function(service){ 
     var length = _.reject(array, function(el){
           return (el.id.indexOf(service) < 0); 
     }).length; 
     return {id: service, count: length};
});

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