blocks|key|1583407|text|就我个人而言，我发现这是最干净的-不确定这是否是最有效的，头脑！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1583408|if+(is_array($values)+%7C%7C+is_object($values))
{
++++foreach+($values+as+$value)
++++{
++++++++...
++++}
}|code-block|syntax|javascript|1583409|我选择的原因是，当您开始没有什么东西的时候，它不会分配空数组。|1583410|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Personally I find this to be the most clean - not sure if it's the most efficient, mind!

<pre><code>if (is_array($values) || is_object($values))
{
 foreach ($values as $value)
 {
 ...
 }
}
</code></pre>

The reason for my preference is it doesn't allocate an empty array when you've got nothing to begin with anyway.

blocks|key|33408|text|首先，必须初始化每个变量。一直都是。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|33409|铸造不是一种选择。|33410|如果get_values()；可以返回不同类型的变量，那么当然必须检查这个值。|33411|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

First of all, every variable must be initialized. Always. 
Casting is not an option. 
if get_values(); can return different type variable, this value must be checked, of course.

blocks|key|33427|text|<?php
+if+(isset($_POST['checkbox']))+{
++++$checkbox+=+$_POST['checkbox'];
++++foreach+($checkbox+as+$key)+{
+++++++echo+$key+.+' ';
++++}
}

?>
++++<input+type="checkbox"+name="checkbox[]"+value="red">red+ 
++++<input+type="checkbox"+name="checkbox[]"+value="green">green+ |type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|33428|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>&lt;?php
 if (isset($_POST['checkbox'])) {
 $checkbox = $_POST['checkbox'];
 foreach ($checkbox as $key) {
 echo $key . '&lt;br&gt;';
 }
}

?&gt;
 &lt;input type=&quot;checkbox&quot; name=&quot;checkbox[]&quot; value=&quot;red&quot;&gt;red &lt;br&gt;
 &lt;input type=&quot;checkbox&quot; name=&quot;checkbox[]&quot; value=&quot;green&quot;&gt;green &lt;br&gt;
</code></pre>

blocks|key|1583497|text|我通常使用类似于此的结构：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1583498|/**
+*+Determine+if+a+variable+is+iterable.+i.e.+can+be+used+to+loop+over.
+*
+*+@return+bool
+*/
function+is_iterable($var)
{
++++return+$var+!==+null+
++++++++&&+(is_array($var)+
++++++++++++%7C%7C+$var+instanceof+Traversable+
++++++++++++%7C%7C+$var+instanceof+Iterator+
++++++++++++%7C%7C+$var+instanceof+IteratorAggregate
++++++++++++);
}

$values+=+get_values();

if+(is_iterable($values))
{
++++foreach+($values+as+$value)
++++{
++++++++//+do+stuff...
++++}
}|code-block|syntax|javascript|1583499|注意，这个特定的版本没有经过测试，它的输入直接从内存中输入。|1583500|编辑：添加了可穿检查|offset|length|style|BOLD|1583501|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/Traversable^0|0|0|0|0|3|6|2|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|Z|8|@$K|10|L|11|M|N]]|9|@$K|12|L|13|1|14]]|A|$]]|$1|O|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

I usually use a construct similar to this:

<pre><code>/**
 * Determine if a variable is iterable. i.e. can be used to loop over.
 *
 * @return bool
 */
function is_iterable($var)
{
 return $var !== null 
 &amp;&amp; (is_array($var) 
 || $var instanceof Traversable 
 || $var instanceof Iterator 
 || $var instanceof IteratorAggregate
 );
}

$values = get_values();

if (is_iterable($values))
{
 foreach ($values as $value)
 {
 // do stuff...
 }
}
</code></pre>

Note that this particular version is not tested, its typed directly into SO from memory.

Edit: added <a href="http://php.net/Traversable">Traversable</a> check

blocks|key|33475|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|33476|//Force+array
$dataArr+=+is_array($dataArr)+?+$dataArr+:+array($dataArr);
foreach+($dataArr+as+$val)+{
++echo+$val;
}|code-block|syntax|javascript|33477|;)|33478|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Try this:

<pre><code>//Force array
$dataArr = is_array($dataArr) ? $dataArr : array($dataArr);
foreach ($dataArr as $val) {
 echo $val;
}
</code></pre>

;)

blocks|key|1321428|text|似乎还与环境有关：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1321429|我只在dev环境中出现了“无效参数提供了foreach()”错误，而没有在prod中出现错误(我正在处理服务器，而不是本地主机)。|1321430|尽管出现了错误，但var_dump表明数组在那里很好(在app和dev两种情况下都是如此)。|1321431|围绕着if+(is_array($array))的foreach+($array+as+$subarray)解决了问题。|offset|length|style|CODE|1321432|对不起，我无法解释原因，但由于我花了一段时间想出一个解决办法，我想更好地分享这一点作为观察。|1321433|entityMap^0|0|0|0|3|L|P|T|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|S|8|@$H|T|I|U|J|K]|$H|V|I|W|J|K]]|9|@]|A|$]]|$1|L|3|M|5|6|7|X|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|O|$]]

There seems also to be a relation to the environment:

I had that "invalid argument supplied foreach()" error only in the dev environment, but not in prod (I am working on the server, not localhost).

Despite the error a var_dump indicated that the array was well there (in both cases app and dev).

The <code>if (is_array($array))</code> around the <code>foreach ($array as $subarray)</code> solved the problem.

Sorry, that I cannot explain the cause, but as it took me a while to figure a solution I thought of better sharing this as an observation.

blocks|key|1320860|text|这个怎么样？很多清洁剂和所有的单线。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1320861|foreach+((array)+$items+as+$item)+{
+//+...
+}|code-block|syntax|javascript|1320862|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

How about this one? lot cleaner and all in single line.

<pre><code>foreach ((array) $items as $item) {
 // ...
 }
</code></pre>

blocks|key|33573|text|警告为foreach()显示tweet提供的无效参数。去/wp-content/plugins/display-tweets-php。然后将这段代码插入591行，它将完美地运行。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|33574|if+(is_array($tweets))+{
++++foreach+($tweets+as+$tweet)+
++++{
++++++++...
++++}
}|code-block|syntax|javascript|33575|entityMap^0|3|9|S|12|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

Warning invalid argument supplied for <code>foreach()</code> display tweets.
go to <code>/wp-content/plugins/display-tweets-php</code>.
Then insert this code on line number 591, It will run perfectly.

<pre><code>if (is_array($tweets)) {
 foreach ($tweets as $tweet) 
 {
 ...
 }
}
</code></pre>

blocks|key|1583576|text|@Kris代码的更简洁扩展|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1583577|function+secure_iterable($var)
{
++++return+is_iterable($var)+?+$var+:+array();
}

foreach+(secure_iterable($values)+as+$value)
{
+++++//do+stuff...
}|code-block|syntax|javascript|1583578|特别是用于使用内部模板代码。|1583579|<?php+foreach+(secure_iterable($values)+as+$value):+?>
++++...
<?php+endforeach;+?>|1583580|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/15655476/2936460^0|0|7|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|C|$G|H]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|C|$]]]|N|$O|$5|P|Q|R|C|$S|T]]]]

More concise extension of <a href="https://stackoverflow.com/a/15655476/2936460">@Kris's code</a>

<pre><code>function secure_iterable($var)
{
 return is_iterable($var) ? $var : array();
}

foreach (secure_iterable($values) as $value)
{
 //do stuff...
}
</code></pre>

especially for using inside template code 

<pre><code>&lt;?php foreach (secure_iterable($values) as $value): ?&gt;
 ...
&lt;?php endforeach; ?&gt;
</code></pre>

blocks|key|33836|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|33837|需要注意:如果您期望返回特定形式的数组，则这可能会使您失败。这需要更多的检查。|offset|length|style|BOLD|33838|例如，将布尔值转换为数组(array)bool，不是将导致空数组，而是一个包含布尔值作为int：[0=>0]或[0=>1]的元素的数组。|blockquote|CODE|33839|我写了一个快速测试来提出这个问题。。(这是一个备份测试，以防第一个测试url失败。)|33840|测试包括：null、false、true、class、array和undefined。|33841|在使用之前，总是测试您的输入。建议：|33842|快速类型检查：$array+=+is_array($var)+or+is_object($var)+?+$var+:+[]+;|ordered-list-item|33843|方法中的类型暗示阵列在使用foreach和指定返回类型之前|33844|在if中包装|33845|使用try{}catch(){}块|33846|在产品发布前设计适当的代码/测试|33847|要根据适当的形式测试数组，可以在特定的键或者测试数组的深度(当它是一个!)上使用或者测试数组的深度(当它是一个!)。|33848|始终将助手方法解压缩到全局命名空间中，以减少重复代码。|33849|entityMap|0|LINK|mutability|MUTABLE|url|https://3v4l.org/aO76k|1|http://sandbox.onlinephpfunctions.com/code/9384a9343369c4d5f5fb1448ab83984a04d2faf1|2|https://stackoverflow.com/questions/2630013/invalid-argument-supplied-for-foreach/2630032#2630032|3|http://php.net/manual/de/language.oop5.typehinting.php|4|https://wiki.php.net/rfc/return_types|5|https://stackoverflow.com/a/263621/1408287|6^0|0|0|13|0|0|1W|C|B|1C|6|1J|6|0|0|16|0|H|0|N|4|1|0|0|17|5|4|A|5|G|4|L|5|R|5|X|9|0|0|I|0|0|1R|7|1K|0|6|2|0|0|T|4|6|3|L|6|4|0|0|6|0|0|H|2|E|0|0|G|0|0|1M|K|H|5|14|H|6|0|0|R|0^^$0|@$1|2|3|-4|4|5|6|1O|7|@]|8|@]|9|$]]|$1|A|3|B|4|5|6|1P|7|@$C|1Q|D|1R|E|F]]|8|@]|9|$]]|$1|G|3|H|4|I|6|1S|7|@$C|1T|D|1U|E|F]|$C|1V|D|1W|E|J]|$C|1X|D|1Y|E|J]|$C|1Z|D|20|E|J]]|8|@]|9|$]]|$1|K|3|L|4|5|6|21|7|@$C|22|D|23|E|F]]|8|@$C|24|D|25|1|26]|$C|27|D|28|1|29]]|9|$]]|$1|M|3|N|4|5|6|2A|7|@$C|2B|D|2C|E|F]|$C|2D|D|2E|E|J]|$C|2F|D|2G|E|J]|$C|2H|D|2I|E|J]|$C|2J|D|2K|E|J]|$C|2L|D|2M|E|J]|$C|2N|D|2O|E|J]]|8|@]|9|$]]|$1|O|3|P|4|5|6|2P|7|@$C|2Q|D|2R|E|F]]|8|@]|9|$]]|$1|Q|3|R|4|S|6|2S|7|@$C|2T|D|2U|E|F]|$C|2V|D|2W|E|J]]|8|@$C|2X|D|2Y|1|2Z]]|9|$]]|$1|T|3|U|4|S|6|30|7|@$C|31|D|32|E|F]]|8|@$C|33|D|34|1|35]|$C|36|D|37|1|38]]|9|$]]|$1|V|3|W|4|S|6|39|7|@$C|3A|D|3B|E|F]]|8|@]|9|$]]|$1|X|3|Y|4|S|6|3C|7|@$C|3D|D|3E|E|F]|$C|3F|D|3G|E|J]]|8|@]|9|$]]|$1|Z|3|10|4|S|6|3H|7|@$C|3I|D|3J|E|F]]|8|@]|9|$]]|$1|11|3|12|4|S|6|3K|7|@$C|3L|D|3M|E|F]]|8|@$C|3N|D|3O|1|3P]|$C|3Q|D|3R|1|3S]]|9|$]]|$1|13|3|14|4|S|6|3T|7|@$C|3U|D|3V|E|F]]|8|@]|9|$]]|$1|15|3|-4|4|5|6|3W|7|@]|8|@]|9|$]]]|16|$17|$4|18|19|1A|9|$1B|1C]]|1D|$4|18|19|1A|9|$1B|1E]]|1F|$4|18|19|1A|9|$1B|1G]]|1H|$4|18|19|1A|9|$1B|1I]]|1J|$4|18|19|1A|9|$1B|1K]]|1L|$4|18|19|1A|9|$1B|1M]]|1N|$4|18|19|1A|9|$1B|1M]]]]

Please do not depend on casting as a solution,
even though others are suggesting this as a valid option to prevent an error, it might cause another one.

Be aware: If you expect a specific form of array to be returned, this might fail you. More checks are required for that.

<blockquote>
 E.g. casting a boolean to an array <code>(array)bool</code>, will NOT result in an empty array, but an array with one element containing the boolean value as an int: <code>[0=&gt;0]</code> or <code>[0=&gt;1]</code>.
</blockquote>

<a href="https://3v4l.org/aO76k" rel="noreferrer">I wrote a quick test to present this problem</a>.
(Here is a <a href="http://sandbox.onlinephpfunctions.com/code/9384a9343369c4d5f5fb1448ab83984a04d2faf1" rel="noreferrer">backup Test</a> in case the first test url fails.)

Included are tests for: <code>null</code>, <code>false</code>, <code>true</code>, a <code>class</code>, an <code>array</code> and <code>undefined</code>.

<hr>

Always test your input before using it in foreach. Suggestions: 

<ol>
<li><a href="https://stackoverflow.com/questions/2630013/invalid-argument-supplied-for-foreach/2630032#2630032">Quick type checking</a>: <code>$array = is_array($var) or is_object($var) ? $var : [] ;</code></li>
<li><a href="http://php.net/manual/de/language.oop5.typehinting.php" rel="noreferrer">Type hinting arrays</a> in methods before using a foreach and <a href="https://wiki.php.net/rfc/return_types" rel="noreferrer">specifying return types</a></li>
<li>Wrapping foreach within if</li>
<li>Using <code>try{}catch(){}</code> blocks</li>
<li>Designing proper code / testing before production releases</li>
<li>To test an array against proper form you could use <code>array_key_exists</code> on a specific key, <a href="https://stackoverflow.com/a/263621/1408287">or test the depth of an array (when it is one !)</a>.</li>
<li>Always extract your helper methods into the global namespace in a way to reduce duplicate code</li>
</ol>

blocks|key|1321003|text|foreach+($arr+?:+[]+as+$elem)+{
++++//+Do+something
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1321004|这不检查它是否为数组，但如果变量为null或空数组，则跳过循环。|unstyled|1321005|从PHP7.0更新您应该使用零聚结算子|offset|length|1321006|foreach+($arr+??+[]+as+$elem)+{
++++//+Do+something
}|1321007|这将解决注释中提到的警告(这里是比较?:和??输出的方便表)。|style|CODE|1321008|entityMap|0|LINK|mutability|MUTABLE|url|https://www.php.net/manual/en/migration70.new-features.php#migration70.new-features.null-coalesce-op|1|https://www.designcise.com/web/tutorial/whats-the-difference-between-null-coalescing-operator-and-ternary-operator-in-php#vs^0|0|0|E|5|0|0|0|I|2|L|2|D|2|1|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|11|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|12|8|@]|9|@$I|13|J|14|1|15]]|A|$]]|$1|K|3|L|5|6|7|16|8|@]|9|@]|A|$B|C]]|$1|M|3|N|5|F|7|17|8|@$I|18|J|19|O|P]|$I|1A|J|1B|O|P]]|9|@$I|1C|J|1D|1|1E]]|A|$]]|$1|Q|3|-4|5|F|7|1F|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]|Y|$5|T|U|V|A|$W|Z]]]]

<pre><code>foreach ($arr ?: [] as $elem) {
 // Do something
}
</code></pre>
This doesen't check if it is an array, but skips the loop if the variable is null or an empty array.
Update from PHP 7.0 you should use the <a href="https://www.php.net/manual/en/migration70.new-features.php#migration70.new-features.null-coalesce-op" rel="nofollow noreferrer">null coalescing operator</a>:
<pre><code>foreach ($arr ?? [] as $elem) {
 // Do something
}
</code></pre>
This would solve the warning mentioned in the comment (<a href="https://www.designcise.com/web/tutorial/whats-the-difference-between-null-coalescing-operator-and-ternary-operator-in-php#vs" rel="nofollow noreferrer">here</a> a handy table that compares <code>?:</code> and <code>??</code> outputs).

blocks|key|1321602|text|如果在foreach循环中将数组设置为null，则会发生此通知的例外情况。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1321603|if+(is_array($values))
{
++++foreach+($values+as+$value)
++++{
++++++++$values+=+null;//WARNING!!!
++++}
}|code-block|syntax|javascript|1321604|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Exceptional case for this notice occurs if you set array to null inside foreach loop 

<pre><code>if (is_array($values))
{
 foreach ($values as $value)
 {
 $values = null;//WARNING!!!
 }
}
</code></pre>

blocks|key|1583814|text|$values+=+get_values();

foreach+((array)+$values+as+$value){
++...
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1583815|问题总是零的，铸造实际上是清洁的解决方案。|unstyled|1583816|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>$values = get_values();

foreach ((array) $values as $value){
 ...
}
</code></pre>

Problem is always null and Casting is in fact the cleaning solution.

blocks|key|1321047|text|如果您使用的是php7，并且只想处理未定义的错误，这是最干净的IMHO|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1321048|$array+=+[1,2,3,4];
foreach+(+$array+??+[]+as+$item+)+{
++echo+$item;
}|code-block|syntax|javascript|1321049|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you're using php7 and you want to handle only undefined errors this is the cleanest IMHO

<pre><code>$array = [1,2,3,4];
foreach ( $array ?? [] as $item ) {
 echo $item;
}
</code></pre>

blocks|key|33992|text|我将使用empty、isset和is_array的组合|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|33993|$array+=+['dog',+'cat',+'lion'];

if+(!empty($array)+&&+isset($array)+&&+is_array($array)+{
++++//loop
++++foreach+($array+as+$values)+{
++++++++echo+$values;+
++++}
}|code-block|syntax|javascript|33994|entityMap^0|4|5|A|5|G|8|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|U|8|@]|D|@]|E|$]]]|L|$]]

I'll use a combination of <code>empty</code>, <code>isset</code> and <code>is_array</code> as

<pre><code>$array = ['dog', 'cat', 'lion'];

if (!empty($array) &amp;&amp; isset($array) &amp;&amp; is_array($array) {
 //loop
 foreach ($array as $values) {
 echo $values; 
 }
}
</code></pre>

blocks|key|1583871|text|使用is_array函数，当您将数组传递给foreach循环时.|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|1583872|if+(is_array($your_variable))+{
++foreach+($your_variable+as+$item)+{
+++//your+code
}
}|code-block|syntax|javascript|1583873|entityMap^0|0|W|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Use is_array function, when you will pass array to foreach loop.

<pre><code>if (is_array($your_variable)) {
 foreach ($your_variable as $item) {
 //your code
}
}
</code></pre>

blocks|key|1583900|text|这个解决方案怎么样：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1583901|$type+=+gettype($your_iteratable);
$types+=+array(
++++'array',
++++'object'
);

if+(in_array($type,+$types))+{
++++//+foreach+code+comes+here
}|code-block|syntax|javascript|1583902|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

How about this solution:

<pre><code>$type = gettype($your_iteratable);
$types = array(
 'array',
 'object'
);

if (in_array($type, $types)) {
 // foreach code comes here
}
</code></pre>

blocks|key|34045|text|如果get_value()是空的，那么将空数组定义为回退如何？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|34046|我想不出最短的路。|34047|$values+=+get_values()+?:+[];

foreach+($values+as+$value){
++...
}|code-block|syntax|javascript|34048|entityMap^0|2|B|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

What about defining an empty array as fallback if <code>get_value()</code> is empty? 
I can't think of a shortest way.

<pre><code>$values = get_values() ?: [];

foreach ($values as $value){
 ...
}
</code></pre>

blocks|key|1583950|text|从PHP7.1.0开始使用is_iterable++>=|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|1583951|https://www.php.net/manual/en/function.is-iterable.php|1583952|if+(is_iterable($value))+{
++++foreach+($value+as+$v)+{
++++++++...
++++}
}|code-block|syntax|javascript|1583953|entityMap|0|LINK|mutability|MUTABLE|url^0|D|B|P|3|D|B|0|0|1I|0|1I|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|11|8|@$9|12|A|13|B|C]]|E|@$9|14|A|15|1|16]]|F|$]]|$1|I|3|J|5|K|7|17|8|@]|E|@]|F|$L|M]]|$1|N|3|-4|5|6|7|18|8|@]|E|@]|F|$]]]|O|$P|$5|Q|R|S|F|$T|H]]]]

As of PHP &gt;= 7.1.0 use <code>is_iterable</code>
<a href="https://www.php.net/manual/en/function.is-iterable.php" rel="nofollow noreferrer">https://www.php.net/manual/en/function.is-iterable.php</a>
<pre><code>if (is_iterable($value)) {
 foreach ($value as $v) {
 ...
 }
}
</code></pre>

blocks|key|1321109|text|之所以出现此警告，是因为要使用的数组为空，可以使用以下条件：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1321110|if+($your_array+!=+false){
+++foreach+($your_array+as+$value){
+++++++++echo+$value['your_value_name'];
++++}
}|code-block|syntax|javascript|1321111|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This warning is happening because the array that you want use is empty, you can use of below condition:
<pre><code>if ($your_array != false){
 foreach ($your_array as $value){
 echo $value['your_value_name'];
 }
}
</code></pre>

It often happens to me to handle data that can be either an array or a null variable and to feed some <code>foreach</code> with these data.

<pre><code>$values = get_values();

foreach ($values as $value){
 ...
}
</code></pre>

When you feed a foreach with data that are not an array, you get a warning:

<blockquote>
 Warning: Invalid argument supplied for foreach() in [...]
</blockquote>

Assuming it's not possible to refactor the <code>get_values()</code> function to always return an array (backward compatibility, not available source code, whatever other reason), I'm wondering which is the cleanest and most efficient way to avoid these warnings:

<ul>
<li>Casting <code>$values</code> to array</li>
<li>Initializing <code>$values</code> to array</li>
<li>Wrapping the <code>foreach</code> with an <code>if</code></li>
<li>Other (please suggest)</li>
</ul>

Invalid argument supplied for foreach()

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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我经常遇到这样的情况:处理可以是数组或空变量的数据，并向一些foreach提供这些数据。$values = get_values();foreach ($values as $value){  ...}当您用非数组的数据填充外汇时，您会得到一个警告：警告:为.中的foreach()提供的无效参数假设重构get_valu...

问为foreach()提供的无效参数
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问为foreach()提供的无效参数EN