Javascript 如何从javascript数组中选择特定字段
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How to select a particular field from javascript array
提问by Kavitha K Gowd
I have an array object in javascript. I would to select a particular field from all the rows of the object.
我在 javascript 中有一个数组对象。我想从对象的所有行中选择一个特定的字段。
I have an object like
我有一个像
var sample = {
[Name:"a",Age:1],
[Name:"b",Age:2],
[Name:"c",Age:3]
}
I would like to get an output of only Names as ["a","b","c"]without looping over sample object.
我想获得仅 Names 的输出，["a","b","c"]而不需要循环遍历示例对象。
How can I select one or two fields using jlinq? or any other plugin?
如何使用 jlinq 选择一两个字段？或任何其他插件？
Thanks a lot.
非常感谢。
采纳答案by Jamiec
You've got your definition the wrong way round. Instead of having an object containing 3 arrays, you want an array of objects.
你的定义是错误的。您需要一个对象数组，而不是包含 3 个数组的对象。
like this:
像这样：
var sample = [{Name:"a",Age:1},
{Name:"b",Age:2},
{Name:"c",Age:3}];
Then you can do:
然后你可以这样做：
var name0 = sample[0].Name;
var age0 = sample[0].Age;
or to get all your names as per your example:
或根据您的示例获取您的所有姓名：
var names = [sample[0].Name,sample[1].Name,sample[2].Name];
But, without looping im not sure how you would get any number of values.... why no looping?
但是，如果不循环，我不确定您将如何获得任意数量的值……为什么不循环？
Just say you do loop, here's how you would do it:
只是说你做循环，这是你的方法：
var names = []
for(x in sample)
names.push(sample[x].Name);
or with jQuery (which is still looping)
或使用 jQuery（仍在循环中）
sample= jQuery.map(sample, function(n, i){
return n.Name;
});
回答by Stéphan
You can try this:
你可以试试这个：
var sample = [{Name:"a", Age:1}, {Name:"b", Age:2}, {Name:"c", Age:3}];
var Names = sample.map(function(item){return item.Name;});
回答by Paul
That Javascript has no meaning. It is syntatically incorrect. I assume you meant:
那个 Javascript 没有意义。它在语法上是不正确的。我假设你的意思是：
var sample = [
{Name:"a",Age:1},
{Name:"b",Age:2},
{Name:"c",Age:3}
]
Then you can use jQuery to do something like this:
然后你可以使用 jQuery 来做这样的事情：
var names = $(sample).map(function(){ return this.Name; });
But in reality all jQuery is doing is looping through the object for you. Writing your own loop would be (insignificantly) faster. There is no way to do this without a loop.
但实际上，jQuery 所做的只是为您遍历对象。编写自己的循环会（微不足道）更快。没有循环就没有办法做到这一点。
回答by cwallenpoole
// assuming you mean:
var sample = [
{Name:"a",Age:1},
{Name:"b",Age:2},
{Name:"c",Age:3}
]
Well, your biggest problem there is that no matter what happens, you'll have to loop. Now, jQuery will let you hide that behavior with:
好吧，你最大的问题是无论发生什么，你都必须循环。现在，jQuery 将允许您通过以下方式隐藏该行为：
var output = []
$.each( sample, function(i,e){ output.push( e.Name )} );
But fundamentally, that is the same thing as:
但从根本上说，这与以下内容相同：
for( var i = 0; i < sample.length; i++ )
{
output.push( v.Name )
}
