如何订购对象中的物品? [英] How can I order the items in an Object?

问题描述

我想用node.js计算字符串的出现次数，并开始实现如下所示的字典:

I want to count the number of occurrences of strings with node.js and started to implement a dictionary like below:

var dict = {}

// Example content ("string" = count)
dict["alpha"] = 12
dict["beta"] = 39

// Increment count (working)
dict["alpha"]++

但是如何将字典从高到低排序?有内置的排序功能，还是我必须自己实现?

But how do I sort this dictionary from highest to lowest count? Is there any built in sorting or do I have to implement this myself?

我想列出文件中从最高计数到最低计数的输出，每行分别是:

I want to list the output from highest to lowest count in a file, with each line being:

<count> <string>

推荐答案

从Rob的答案继续，您可以将这些对象放入对象排序数组中，其值如下:

Continuing from the Rob's answer, you could get the items in sorted array of objects having the values like this:

var res = Object.keys(dict).map(function(key ) {
  return { key: key, value : dict[key] };
}).sort(function(a, b) { 
   return b.value - a.value
});

其中res是[{key:"alpha"，value:16}，...]形式的排序数组

Where res is sorted array of form [{key:"alpha",value:16},...]

然后可以使用reduce将哪些转换为字符串

Which can then be converted to string using reduce

var strToFile = res.reduce( function(p,n) { 
 return p + n.value+" "+n.key+"\n"; },"");

结果看起来像

39 beta
12 alpha

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