数组：第四维，isset 返回不可靠
有谁知道这段代码怎么会与 yahoo 相呼应？显然没有第四个数组带有键“something”，但它一直认为是这样的。漏洞？特征？
$array = array('a' => array('b' => array('c' => 'test')));
echo '<pre>';
var_dump($array);
echo '</pre>';
if (isset($array['a']['b']['c']['something'])) {
echo 'yahoo';
}
Does anybody know, how it can be, that this code echoes yahoo? There is clearly no 4th array with the key 'something', but it keeps thinking it's like that. Bug? Feature?
$array = array('a' => array('b' => array('c' => 'test')));
echo '<pre>';
var_dump($array);
echo '</pre>';
if (isset($array['a']['b']['c']['something'])) {
echo 'yahoo';
}
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因为 PHP 认为您正在检查字符串“test”的“something”位置。请记住，字符串是字符数组。尝试回显 $array['a']['b']['c']['something']。
::编辑::
我解释了它，我并没有说它有道理。 ：P
Because PHP thinks you are checking the 'something'th place of the string 'test'. Remember, strings are arrays of characters. try to echo $array['a']['b']['c']['something'].
::EDIT::
I Explained it, I didn't say it made sense. :P
这里讨论了 PHP 在这个问题上的行为并提供了一个完全适合您问题的解决方案。
Here has discussed the behavior of PHP in this issue and provides a solution that is exactly for your problem.
您想要使用
is_array($array['a']['b']['c'])而不是isset($array['a']['b ']['c']['something'])在这种情况下，或者可能是两者的巧妙组合，以确保在检查时未设置时不会收到任何错误如果它是一个数组。像这样的东西：
You'd want to use
is_array($array['a']['b']['c'])rather thanisset($array['a']['b']['c']['something'])in this case, or maybe a crafty combination of the two to make sure you don't get any errors if it's not set when you're checking to see if it's an array.Something like: