问题
I am stuck in comparing two unicode strings in PHP which both contain the special char 'ö'. One string comes from $_GET, the other one is a filesystem's folder name (scandir()). Both strings seem to be equal to me, making a
var_dump($filter);
var_dump($tail . '/' . $k);
on them also shows their equality but with different string lenghts (?!):
string '/blöb' (length=7)
string '/blöb' (length=6)
My snippet comparing them looks as follows:
if($filter == ($tail . '/' . $k)) {
/* ... */
}
What's going on here?
Additional information: $tail is an empty string:
string '' (length=0)
回答1:
See here: http://en.wikipedia.org/wiki/Unicode_equivalence and use this: http://www.php.net/manual/en/class.normalizer.php
You probably have a decomposed character in the longer string, meaning an o and then a umlaut combining character which overlays the previous character.
The normalizer function will fix things like that.
As a side note you should always normalize your input if you are using it for equivalence (for example a username - you want to make sure two people don't choose the same username, even if the binary representation of the string happens to be different).
回答2:
Can you try parsing them through utf8_encode() and checking them there? PHP doesn't support unicode and therefore advises to use utf8_encode/decode for some basic Unicode features.
http://php.net/manual/en/language.types.string.php
来源：https://stackoverflow.com/questions/6855425/comparing-two-unicode-strings-in-php