.countByを使用してデータを要約する

Question

_.countBy()メソッドを使用してUnderscoreJSに次のデータを要約する方法を試しています。

var data = 
[ 
    {"id":"338b79f07dfe8b3877b3aa41a5bb8a58","value":{"country":"United States"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a5bb983e","value":{"country":"Norway"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a5ddfefe","value":{"country":"Hungary"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a5fe29d7","value":{"country":"United States"}}, 
    {"id":"b6ed02fb38d6506d7371c419751e8a14","value":{"country":"Germany"}}, 
    {"id":"b6ed02fb38d6506d7371c419753e20b6","value":{"country":"Hungary"}}, 
    {"id":"b6ed02fb38d6506d7371c419755f34ad","value":{"country":"United States"}}, 
    {"id":"b6ed02fb38d6506d7371c419755f3e17","value":{"country":"Germany"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a506082f","value":{"country":"United Kingdom"}}, 
    {"id":"9366afb036bf8b63c9f45379bbe29509","value":{"country":"United Kingdom"}} 
] 

私はこのようにそれを要約したい：私はUnderscore.jsが提供する_.countBy()方法にこれを渡す方法

{ 
    United_States: 3, 
    Norway: 1, 
    Hungary: 2, 
    Germany: 2, 
    United_Kingdom: 2 
} 

私は、次のデータがありますか？

Answer 1

これを試してみてください：

var data = 
[ 
    {"id":"338b79f07dfe8b3877b3aa41a5bb8a58","value":{"country":"United States"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a5bb983e","value":{"country":"Norway"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a5ddfefe","value":{"country":"Hungary"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a5fe29d7","value":{"country":"United States"}}, 
    {"id":"b6ed02fb38d6506d7371c419751e8a14","value":{"country":"Germany"}}, 
    {"id":"b6ed02fb38d6506d7371c419753e20b6","value":{"country":"Hungary"}}, 
    {"id":"b6ed02fb38d6506d7371c419755f34ad","value":{"country":"United States"}}, 
    {"id":"b6ed02fb38d6506d7371c419755f3e17","value":{"country":"Germany"}}, 
    {"id":"338b79f07dfe8b3877b3aa41a506082f","value":{"country":"United Kingdom"}}, 
    {"id":"9366afb036bf8b63c9f45379bbe29509","value":{"country":"United Kingdom"}} 
]; 

var countData = _.countBy(data, function(obj){ 
    return obj.value.country.replace(" ", "_"); 
}); 

console.log(countData); 

JSFiddle：http://jsfiddle.net/hyDv7/1/

Answer 2

"クリーンJS"：

var t = {}; 
for(var i = 0, l = data.length; i < l; i++){ 
    t[data[i].value.country] = !t[data[i].value.country] ? 1 : t[data[i].value.country] + 1; 
} 

結果：余談として

Germany 2 
Hungary 2 
Norway 1 
United Kingdom 2 
United States 3