(Don't you hate it when people forget to post back to the list...) The secret is actually hidden in the docs, http://php.net/manual/en/language.operators.comparison.php When comparing $a < $b, you compare the first value of $a (0) to the value with the same key in $b (1). 0 < 1 --> true When you compare $b < $a, the first value of $b is 0, with a key of 1. The value in $a is 1, 0 < 1 --> true The discussion on php-dev, where you found this example, reveals that PHP makes the assumption that $a > $b == $b < $a. This means that they can reuse the less than function for greater than calls. In this case the assumption isn't actually valid. $a > $b should be 0 > 1 --> false. David Jochem Maas wrote: > THIS CODE > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > php -r ' > $a = array(0, 1); > $b = array(1 => 0, 0 => 1); > var_dump($a < $b); // true > var_dump($a > $b); // true > var_dump($b < $a); > var_dump($b > $a); > > echo "\n\$a:\n"; var_dump((bool)$a, (int)$a, (string)$a, intval($a), > strval($a)); > echo "\n\$b:\n"; var_dump((bool)$b, (int)$b, (string)$b, intval($b), > strval($b)); > ' > > OUTPUTS (on php5.0.4): > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > bool(true) > bool(true) > bool(true) > bool(true) > > $a: > bool(true) > int(1) > string(5) "Array" > > $b: > bool(true) > int(1) > string(5) "Array" > > WHICH MEANS THAT: > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > one the one hand $a is greater than AND less than $b > but on the other hand casting $a OR $b to either a boolean, > integer or string results in the exact same value. ie: > > php -r ' > $a = array(0, 1); $b = array(1 => 0, 0 => 1); > var_dump( ((($a > $b) === ($b > $a)) === ((int)$a === (int)$b)) ); // > WTF IT'S TRUE > ' > > weird? I think so - but then again I'd never test that array $a is > greater than array $b because this is meaningless to me (in what way is $a > greater - how is this quantified, what 'rules' determine 'greatness' in > this context?) > > PS - changing the $b array to something else (anything else as far as i > can tell) > causes the weirdness to not occur - which gives me the impression this > could be a bug, > anyone else get this impression? for instance try changing the second > line of > the code above to (merely switching the order or the defined array > elements): > > $b = array(0 => 1, 1 => 0); > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
