PHP 致命错误：无法重新分配 $this
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PHP Fatal error: Cannot re-assign $this
提问by Arlen Beiler
I get this error from my script:
我从我的脚本中得到这个错误：
[Fri Apr 23 10:57:42 2010] [error] [client 10.0.0.1] PHP Fatal error: Cannot re-assign $this in C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\abp\fol\test.php on line 27, referer: http://abp.bhc.com/fol/
Here is the code which produces the error:
这是产生错误的代码：
<?php
$voiceboxes = array(
'141133' => array(
'title' => 'Title',
'1' => array(
'Title' => 'Title2',
'Link' => 'http://...',
),
'12' => array(
'Title' => 'Title3',
'Link' => 'http://...',
)
),
'1070453' => array(
'title' => 'Title4',
'1' => array(
'Title' => 'Title5',
'Link' => 'http://...',
)
)
);
$last = 0;
//$this = 0;
echo "<ol>\n";
foreach ($voiceboxes as $key => $value) {
$last = 0;
$this = null; //Error is thrown here, Line 27
//$voiceboxes[$key]['title']
echo "<ol>\n";
foreach ($value as $key2 => $value2) {
if ($key2 == 'title') {
echo "<li>$value2</li>\n";
} else {
$this = (int) $key2;
if ($this == $last + 1) {
echo '<li>';
} else { '<li value="' . $key2 . '">';}
$last = $key2;
echo $voiceboxes[$key][$key2]['Title'] . "<br/>" . $voiceboxes[$key][$key2]['Link'] . '</li>' . "\n";
}
}
echo "</ol>\n";
}
回答by Oddthinking
$thisis a predefined variable in PHP.
$this是 PHP 中的预定义变量。
Here's the reference in the PHP manual: Classes and Objects: The Basics. It describes how, inside a method, $this points to "this object" that is being operated upon. It is still reserved outside a method, though.
这是 PHP 手册中的参考资料：Classes and Objects: The Basics。它描述了在一个方法中，$this 如何指向正在被操作的“这个对象”。不过，它仍然保留在方法之外。
Change the identifier to another word.
将标识符更改为另一个词。
回答by meagar
$thisis a special variable in php. If this code is taking place inside a class, $thisis a reference to the object the method is being invoked on. You cannot assign a new value to $thisinside of a class. It is a limitation of PHP that you also cannot assign to a variable named $thisoutside of a class, where it would otherwise be valid to do so.
$this是php中的一个特殊变量。如果此代码发生在类内部，$this则是对调用方法的对象的引用。您不能$this在类内部分配新值。PHP 的一个限制是，您也不能分配给$this在类之外命名的变量，否则这样做是有效的。
I believe this was valid in PHP4, but as of PHP5 You'll have to choose a new variable name.
我相信这在 PHP4 中是有效的，但是从 PHP5 开始，您必须选择一个新的变量名称。
回答by phimuemue
I'm not really a PHP expert, but i think $thisis referring to the current object, so if you set thisto null, you try to set the current object to nothing, wich can not work.
我不是真正的 PHP 专家，但我认为$this是指当前对象，所以如果您设置this为null，则尝试将当前对象设置为空，这将无法正常工作。
回答by Parameshwaran Manickkam
You can reassign $thisvalue by variable variable
您可以$this通过变量变量重新分配值
$name = 'this';
$$name = 'stack';
echo $this;
// this will result stack
