blocks|key|232874|text|有两种方法可以做到这一点|type|unstyled|depth|inlineStyleRanges|entityRanges|data|232875|foreach($questions+as+$key+=>+$question){
++++$questions[$key]['answers']+=+$answers_model->get_answers_by_question_id($question['question_id']);
}|code-block|syntax|javascript|232876|这样就可以保存密钥，这样就可以在主$questions变量中再次更新它|offset|length|style|CODE|232877|或|232878|foreach($questions+as+&$question){|232879|添加&将使$questions保持更新。但是我想说第一个是推荐的，尽管这个比较短(参见Paystey的评论)|232880|每个the+PHP+foreach+documentation|232881|232882|为了能够直接修改循环中的数组元素，在$value前面加上&。在这种情况下，该值将通过引用赋值。|blockquote|232883|232884|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/control-structures.foreach.php^0|0|0|H|A|0|0|0|2|1|5|A|0|A|7|2|T|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|17|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|18|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|19|8|@$I|1A|J|1B|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|1C|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1E|8|@$I|1F|J|1G|K|L]|$I|1H|J|1I|K|L]]|9|@]|A|$]]|$1|S|3|T|5|6|7|1J|8|@$I|1K|J|1L|K|L]]|9|@$I|1M|J|1N|1|1O]]|A|$]]|$1|U|3|-4|5|6|7|1P|8|@]|9|@]|A|$]]|$1|V|3|W|5|X|7|1Q|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1R|8|@]|9|@]|A|$]]|$1|Z|3|-4|5|6|7|1S|8|@]|9|@]|A|$]]]|10|$11|$5|12|13|14|A|$15|16]]]]

There are 2 ways of doing this

<pre><code>foreach($questions as $key =&gt; $question){
 $questions[$key]['answers'] = $answers_model-&gt;get_answers_by_question_id($question['question_id']);
}
</code></pre>

This way you save the key, so you can update it again in the main <code>$questions</code> variable

or

<pre><code>foreach($questions as &amp;$question){
</code></pre>

Adding the <code>&amp;</code> will keep the <code>$questions</code> updated. But I would say the first one is recommended even though this is shorter (see comment by Paystey)

Per <a href="http://php.net/manual/en/control-structures.foreach.php" rel="noreferrer">the PHP <code>foreach</code> documentation</a>:

<blockquote>
 In order to be able to directly modify array elements within the loop precede $value with &amp;. In that case the value will be assigned by reference.
</blockquote>

blocks|key|229075|text|当然，使用array_map和使用实现ArrayAccess的容器来派生对象只是一种更智能、更具语义的方式吗？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|229076|在我见过的大多数语言和实现中，数组映射语义都是相似的。它旨在根据输入数组元素(高级忽略语言编译/运行时类型首选项)返回修改后的数组；循环的目的是执行更多的逻辑。|229077|为了通过ID+/+PK检索对象，取决于您是否在使用SQL+(这似乎是建议的)，我会使用一个过滤器来确保我得到一个有效的PK数组，然后用逗号内爆并放入一个SQL+IN()子句中以返回结果集。它通过SQL进行一次调用，而不是多次调用，优化了一点call->wait周期。最重要的是，我的代码对于具有一定能力的任何语言的人来说都可以很好地阅读，并且我们不会遇到可变性问题。|229078|<?php

$arr+=+[0,1,2,3,4];
$arr2+=+array_map(function($value)+{+return+is_int($value)+?+$value*2+:+$value;+},+$arr);
var_dump($arr);
var_dump($arr2);|code-block|syntax|javascript|229079|vs|229080|<?php

$arr+=+[0,1,2,3,4];
foreach($arr+as+$i+=>+$item)+{
++++$arr[$i]+=+is_int($item)+?+$item+*+2+:+$item;
}
var_dump($arr);|229081|如果你知道你正在做的事情永远不会有易变性的问题(记住，如果你打算重写$arr，你总是可以$arr+=+array_map并显式的。|229082|entityMap^0|5|9|J|B|0|0|28|4|3C|A|0|0|0|0|Y|4|18|G|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|J|3|K|5|L|7|17|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|18|8|@]|D|@]|E|$]]|$1|Q|3|R|5|L|7|19|8|@]|D|@]|E|$M|N]]|$1|S|3|T|5|6|7|1A|8|@$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]]|V|$]]

Surely using <code>array_map</code> and if using a container implementing <code>ArrayAccess</code> to derive objects is just a smarter, semantic way to go about this?

Array map semantics are similar across most languages and implementations that I've seen. It's designed to return a modified array based upon input array element (high level ignoring language compile/runtime type preference); a loop is meant to perform more logic.

For retrieving objects by ID / PK, depending upon if you are using SQL or not (it seems suggested), I'd use a filter to ensure I get an array of valid PK's, then implode with comma and place into an SQL <code>IN()</code> clause to return the result-set. It makes one call instead of several via SQL, optimising a bit of the <code>call-&gt;wait</code> cycle. Most importantly my code would read well to someone from any language with a degree of competence and we don't run into mutability problems.

<pre><code>&lt;?php

$arr = [0,1,2,3,4];
$arr2 = array_map(function($value) { return is_int($value) ? $value*2 : $value; }, $arr);
var_dump($arr);
var_dump($arr2);
</code></pre>

vs

<pre><code>&lt;?php

$arr = [0,1,2,3,4];
foreach($arr as $i =&gt; $item) {
 $arr[$i] = is_int($item) ? $item * 2 : $item;
}
var_dump($arr);
</code></pre>

If you know what you are doing will never have mutability problems (bearing in mind if you intend upon overwriting <code>$arr</code> you could always <code>$arr = array_map</code> and be explicit.

I was wondering if it is possible to edit the current object that's being handled within a <code>foreach</code> loop

I'm working with an array of objects <code>$questions</code> and I want to go through and look for the answers associated with that question object in my db. So for each question go fetch the answer objects and update the current <code>$question</code> inside my <code>foreach</code> loop so I can output/process elsewhere.

<pre><code>foreach($questions as $question){
 $question['answers'] = $answers_model-&gt;get_answers_by_question_id($question['question_id']);
}
</code></pre>

Modify array values in foreach loop

数据库

容器

我想知道是否可以编辑正在foreach循环中处理的当前对象我正在处理一个对象数组$questions，我希望在我的数据库中遍历并查找与该问题对象相关的答案。因此，对于每个问题，获取answer对象并更新 my foreach循环中的当前$question ，这样我就可以在其他地方输出/处理。foreach($quest...

问修改foreach循环中的数组值
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