Javascript 如何访问 JSON 对象数组的第一个元素？
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How to access first element of JSON object array?
提问by Hedge
I exptect that mandrill_events only contains one object. How do I access its event-property?
我预计 mandrill_events 只包含一个对象。我如何访问它event-property？
var req = { mandrill_events: '[{"event":"inbound","ts":1426249238}]' }
采纳答案by stovroz
To answer your titular question, you use [0]to access the first element, but as it stands mandrill_eventscontains a string not an array, so mandrill_events[0]will just get you the first character, '['.
为了回答您的名义问题，您使用[0]访问第一个元素，但由于它mandrill_events包含一个字符串而不是数组，因此mandrill_events[0]只会为您提供第一个字符 '['。
So either correct your source to:
因此，要么将您的来源更正为：
var req = { mandrill_events: [{"event":"inbound","ts":1426249238}] };
and then req.mandrill_events[0], or if you're stuck with it being a string, parse the JSON the string contains:
然后req.mandrill_events[0]，或者如果你坚持它是一个字符串，解析字符串包含的 JSON：
var req = { mandrill_events: '[{"event":"inbound","ts":1426249238}]' };
var mandrill_events = JSON.parse(req.mandrill_events);
var result = mandrill_events[0];
回答by Anuga
var req = { mandrill_events: '[{"event":"inbound","ts":1426249238}]' }
console.log(Object.keys(req)[0]);
Make any Object array (req), then simply do Object.keys(req)[0]to pick the first key in the Object array.
创建任何对象数组 ( req)，然后简单Object.keys(req)[0]地选择对象数组中的第一个键。
回答by semirturgay
the event property seems to be string first you have to parse it to json :
事件属性似乎首先是字符串，您必须将其解析为 json ：
var req = { mandrill_events: '[{"event":"inbound","ts":1426249238}]' };
var event = JSON.parse(req.mandrill_events);
var ts = event[0].ts
回答by Dimitris Karagiannis
'[{"event":"inbound","ts":1426249238}]'is a string, you cannot access any properties there. You will have to parse it to an object, with JSON.parse()and then handle it like a normal object
'[{"event":"inbound","ts":1426249238}]'是一个字符串，你不能访问那里的任何属性。您必须将其解析为一个对象，JSON.parse()然后像普通对象一样处理它
回答by Qutayba
After you parse it with Javascript, try this:
用 Javascript 解析后，试试这个：
mandrill_events[0].event
回答by lluisma
Assuming thant the content of mandrill_eventsis an object (not a string), you can also use shift()function:
假设内容mandrill_events是一个对象（不是字符串），您还可以使用shift()函数：
var req = { mandrill_events: [{"event":"inbound","ts":1426249238}] };
var event-property = req.mandrill_events.shift().event;
