blocks|key|590085|text|正如Zack在下面的评论中所说的，您可以使用以下命令简单地重新实例化它|type|unstyled|depth|inlineStyleRanges|entityRanges|data|590086|$foo+=+array();+//+$foo+is+still+here|code-block|syntax|javascript|590087|如果你想要更强大的东西，使用unset，因为它还会从符号表中清除$foo，如果你以后需要这个数组，只需再次实例化它。|590088|unset($foo);+//+$foo+is+gone
$foo+=+array();+//+$foo+is+here+again|590089|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Like Zack said in the comments below you are able to simply re-instantiate it using 

<pre><code>$foo = array(); // $foo is still here
</code></pre>

If you want something more powerful use unset since it also will clear $foo from the symbol table, if you need the array later on just instantiate it again.

<pre><code>unset($foo); // $foo is gone
$foo = array(); // $foo is here again
</code></pre>

blocks|key|374334|text|如果你只想将一个变量重置为一个空数组，你可以简单地重新初始化它：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|374335|$foo+=+array();|code-block|syntax|javascript|374336|请注意，这将保留对它的所有引用：|374337|$foo+=+array(1,2,3);
$bar+=+&$foo;
//+...
$foo+=+array();+//+clear+array
var_dump($bar);+//+array(0)+{+}+--+bar+was+cleared+too!|374338|如果要中断对它的任何引用，请先取消设置它：|374339|$foo+=+array(1,2,3);
$bar+=+&$foo;
//+...
unset($foo);+//+break+references
$foo+=+array();+//+re-initialize+to+empty+array
var_dump($bar);+//+array(3)+{+1,+2,+3+}+--+$bar+is+unchanged|374340|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

If you just want to reset a variable to an empty array, you can simply reinitialize it:

<pre><code>$foo = array();
</code></pre>

Note that this will maintain any references to it:

<pre><code>$foo = array(1,2,3);
$bar = &amp;$foo;
// ...
$foo = array(); // clear array
var_dump($bar); // array(0) { } -- bar was cleared too!
</code></pre>

If you want to break any references to it, unset it first:

<pre><code>$foo = array(1,2,3);
$bar = &amp;$foo;
// ...
unset($foo); // break references
$foo = array(); // re-initialize to empty array
var_dump($bar); // array(3) { 1, 2, 3 } -- $bar is unchanged
</code></pre>

blocks|key|589999|text|如果数组是关联的，我会说第一个。如果没有，请使用for循环：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|590000|for+($i+=+0;+$i+<+count($array);+$i%2B%2B)+{+unset($array[$i]);+}|code-block|syntax|javascript|590001|不过，如果可能的话，使用|590002|$array+=+array();|590003|将数组重置为空数组更可取。|590004|entityMap^0|O|3|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|Y|8|@]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|R|$]]

I'd say the first, if the array is associative. If not, use a <code>for</code> loop:

<pre><code>for ($i = 0; $i &lt; count($array); $i++) { unset($array[$i]); }
</code></pre>

Although if possible, using

<pre><code>$array = array();
</code></pre>

To reset the array to an empty array is preferable.

blocks|key|374251|text|难道unset()还不够好吗？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|374252|unset($array);|code-block|syntax|javascript|374253|entityMap|0|LINK|mutability|MUTABLE|url|http://us3.php.net/manual/en/function.unset.php^0|2|7|2|7|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@$9|V|A|W|1|X]]|E|$]]|$1|F|3|G|5|H|7|Y|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Isn't <a href="http://us3.php.net/manual/en/function.unset.php" rel="noreferrer"><code>unset()</code></a> good enough?

<pre><code>unset($array);
</code></pre>

blocks|key|590112|text|那$array_name+=+array();呢？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|590113|entityMap^0|1|M|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

How about <code>$array_name = array();</code> ?

blocks|key|374440|text|使用array_splice清空数组并保留引用：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|374441|array_splice($myArray,+0);|374442|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.array-splice.php^0|2|C|2|C|0|0|0|Q|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|G|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]]]

Use <a href="http://php.net/manual/en/function.array-splice.php" rel="noreferrer"><code>array_splice</code></a> to empty an array and retain the reference: 

<code>array_splice($myArray, 0);</code>

blocks|key|374503|text|我使用unset()来清除数组，但我逐渐意识到unset()会使数组为空，因此需要重新声明数组，例如|type|unstyled|depth|inlineStyleRanges|entityRanges|data|374504|<?php+
++++$arr+=+array();
++++array_push($arr+,+"foo");
++++unset($arr);+//+this+will+set+the+array+to+null+hence+you+need+the+line+below+or+redeclaring+it.
++++$arr++=+array();

++++//+do+what+ever+you+want+here
?>|code-block|syntax|javascript|374505|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|$]]

i have used unset() to clear the array but i have come to realize that unset() will render the array null hence the need to re-declare the array like for example

<pre><code>&lt;?php 
 $arr = array();
 array_push($arr , "foo");
 unset($arr); // this will set the array to null hence you need the line below or redeclaring it.
 $arr = array();

 // do what ever you want here
?&gt;
</code></pre>

blocks|key|374543|text|我知道这个问题很老了，但是为了解决这个问题，我写了一个递归函数来取消数组中的所有值的设置。递归，因为给定数组的值也可能是数组。所以这对我来说是可行的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|374544|function+empty_array(&+$complete_array)+{
++++foreach($complete_array+as+$ckey+=>+$cvalue)
++++{
++++++++if+(!is_array($cvalue))+{
++++++++++++$complete_array[$ckey]+=+"";
++++++++}+else+{
++++++++++++empty_array(+$complete_array[$ckey]);
++++++++}

++++}
++++return+$complete_array;

}|code-block|syntax|javascript|374545|因此，我得到了包含所有键和子数组的数组，但值为空值。|374546|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|$]]

I see this questions is realla old, but for that problem I wrote a recursive function to unset all values in an array. Recursive because its possible that values from the given array are also an array. So that works for me:

<pre><code>function empty_array(&amp; $complete_array) {
 foreach($complete_array as $ckey =&gt; $cvalue)
 {
 if (!is_array($cvalue)) {
 $complete_array[$ckey] = "";
 } else {
 empty_array( $complete_array[$ckey]);
 }

 }
 return $complete_array;

}
</code></pre>

So with that i get the array with all keys and sub-arrays, but empty values.

blocks|key|590195|text|这是功能强大且经过测试的未设置($gradearray)；//重新设置数组|type|unstyled|depth|inlineStyleRanges|entityRanges|data|590196|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

This is powerful and tested 
unset($gradearray);//re-set the array

blocks|key|374625|text|这些帖子并没有真正回答这个问题。保留键和清除值是问题的焦点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|374626|foreach($resultMasterCleaned['header']+as+$ekey+=>+$eval)+{
++++$resultMasterCleaned[$key][$eval]+=+"";+++++++++++++++++
}|code-block|syntax|javascript|374627|如在保持CSV值的二维数组的情况下，并清空特定行。循环通过似乎是唯一的方法。|374628|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|$]]

The question is not really answered by the posts. Keeping the keys and clearing the values is the focus of the question.
<pre><code>foreach($resultMasterCleaned['header'] as $ekey =&gt; $eval) {
 $resultMasterCleaned[$key][$eval] = &quot;&quot;; 
}
</code></pre>
As in the case of a two dimensional array holding CSV values and to blank out a particular row. Looping through seems the only way.

blocks|key|374677|text|对于PHP+>=+5.4，请使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|374678|$var+=+[];+|code-block|syntax|javascript|374679|我不确定它是否比|374680|$var+=+array();|374681|但至少看起来更干净。|374682|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

For PHP &gt;= 5.4 use
<pre><code>$var = []; 
</code></pre>
Not sure if it's faster than
<pre><code>$var = array();
</code></pre>
but at least looks cleaner.

Which is more efficient for clearing all values in an array? The first one would require me to use that function each time in the loop of the second example.

<pre><code>foreach ($array as $i =&gt; $value) {
 unset($array[$i]);
}
</code></pre>

Or this

<pre><code>foreach($blah_blah as $blah) {
 $foo = array();
 //do something
 $foo = null;
}
</code></pre>

Best way to clear a PHP array's values

在清除数组中的所有值时，哪个更有效？第一个函数要求我在第二个示例的循环中每次都使用该函数。foreach ($array as $i => $value) {    unset($array[$i]);}或者这个foreach($blah_blah as $blah) {    $foo = array();    //do something    $foo = null;}

问清除PHP数组值的最佳方法
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