Is it safe to use this kind of variable swapping in php ?
$a^=$b^=$a^=$b;
Asked
Active
Viewed 285 times
2
-
1*(related)* [Reference - What does this symbol mean in PHP?](http://stackoverflow.com/questions/3737139/reference-what-does-this-symbol-mean-in-php) – Gordon Oct 16 '10 at 09:57
-
Related: http://stackoverflow.com/questions/1998903/php-i-i-crashed-the-server – codaddict Oct 16 '10 at 09:58
-
This sounds like a terrible idea. Imagine what this would do e.g. to objects or arrays – Pekka Oct 16 '10 at 10:23
-
`$a = "cats"; $b = "fail whale";` – salathe Oct 16 '10 at 10:23
2 Answers
6
No, because the variables may not be types that can be XORd the way you expect. The PHP idiom for swapping two variables (of any scalar type) in one line is:
list($a, $b) = array($b, $a);
gregjor
- 20,482
- 1
- 21
- 16
-
Yes it does... I wasn't sure list() worked with arrays but I tried it and it does work. – gregjor Oct 16 '10 at 10:47
-2
Only correct when both are integer. It's readability is poor,and efficiency is not good too,why use it?
matthewyang
- 66
- 7