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|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|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|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|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|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|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|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|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|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|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|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|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|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|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>

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>

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。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

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_values()函数不可能总是返回数组(向后兼容性，没有可用的源代码，不管其他原因如何)

问为foreach()提供的无效参数
EN

回答 20

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问为foreach()提供的无效参数EN

回答 20

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问为foreach()提供的无效参数
EN