blocks|key|718808|text|this.competitors.forEach(competitor)+{
++++var+competitorValue+=+competitor.val();
++++console.log(competitorValue);
++++competitorValue.forEach(sub){
++++++++console.log(sub.val());
++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|718809|这将允许您对所有分支进行解析。|unstyled|718810|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>this.competitors.forEach(competitor) {
 var competitorValue = competitor.val();
 console.log(competitorValue);
 competitorValue.forEach(sub){
 console.log(sub.val());
 }
}
</code></pre>

This will let you parse through all the branches.

blocks|key|1322211|text|你在处理的是可观察的而不是普通的收藏品。这意味着您必须使用可观察的原语，在this.competitors上简单的循环将无法工作。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1322212|这就是：|1322213|this.competitors.subscribe(competitor+=>+console.log(competitor));|code-block|syntax|javascript|1322214|顺便说一句，还有一个命名约定，可以用$来命名可观察的对象，因此它看起来如下：|1322215|this.competitors$+=+af.database.list('/competitors');|1322216|以及：|1322217|this.competitors$.subscribe(competitor+=>+console.log(competitor));|1322218|这将记录整个竞争对手。如果要迭代这些元素，请执行以下操作：|1322219|this.competitors.subscribe(
++++competitors+=>+{
++++++++competitors.map(competitor+=>
++++++++++++console.log(competitor)
++++++++)
++++});|1322220|entityMap^0|11|G|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|13|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|15|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|17|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|U|3|V|5|6|7|19|8|@]|D|@]|E|$]]|$1|W|3|X|5|J|7|1A|8|@]|D|@]|E|$K|L]]|$1|Y|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|Z|$]]

You're working with Observables and not plain collections here. This means that you have to use the Observable primitives and simple looping over <code>this.competitors</code> will not work.

This this:

<pre><code>this.competitors.subscribe(competitor =&gt; console.log(competitor));
</code></pre>

And by the way, there is a naming convention to name Observables with a $ at the end, so it would look the following way:

<pre><code>this.competitors$ = af.database.list('/competitors');
</code></pre>

and:

<pre><code>this.competitors$.subscribe(competitor =&gt; console.log(competitor));
</code></pre>

This will log the entire array of competitors. If you want to iterate over the elements, do something like the following:

<pre><code>this.competitors.subscribe(
 competitors =&gt; {
 competitors.map(competitor =&gt;
 console.log(competitor)
 )
 });
</code></pre>

blocks|key|1322235|text|订阅：next+中的迭代：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|1322236|this.transactions.subscribe({
++next(competitors)+{
++++competitors.forEach(competitor+=>+{
+++++++++console.log(competitor);
++++});
++},
++error(err)+{+console.log('errors+already+caught...+will+not+run');+}
})|code-block|syntax|javascript|1322237|entityMap^0|3|4|8|5|3|4|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|D]]|E|@]|F|$]]|$1|G|3|H|5|I|7|U|8|@]|E|@]|F|$J|K]]|$1|L|3|-4|5|6|7|V|8|@]|E|@]|F|$]]]|M|$]]

Iterate with <code>next</code> in subscribe:

<pre><code>this.transactions.subscribe({
 next(competitors) {
 competitors.forEach(competitor =&gt; {
 console.log(competitor);
 });
 },
 error(err) { console.log('errors already caught... will not run'); }
})
</code></pre>

I have a list observable of objects that I am trying to iterate over to compare a list object property to a local variable.

I can loop over the objects in the list in a template but can't see how to in the component logic.

How can I do this outside of the template?

This is the closest I have gotten to a working iterator so far.

<pre><code>constructor(af: AngularFire) {
 this.competitors = af.database.list('/competitors');
}
this.competitors.forEach(competitor) {
 console.log(competitor);
}
</code></pre>

I'm sorry if this is a question is poorly constructed, I am still quite new to Angular2 and Firebase.

How to iterate over a firebase2 list observable?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我有一个可以观察到的对象列表，我试图迭代这些对象，以便将列表对象属性与局部变量进行比较。我可以在模板中遍历列表中的对象，但是无法在组件逻辑中看到如何循环。如何在模板之外执行此操作？到目前为止，这是我接触到的最近的迭代器。constructor(af: AngularFire) {    this.competitors...

问如何迭代可观察到的firebase2列表？
EN

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问如何迭代可观察到的firebase2列表？EN