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guss at typo dot co dot il
21 years ago
Regarding the recursive sorting function above:
Genrally speaking, any recursion can be reimplemented using simple iteration. in the specific case, using recursion to compare strings has a huge performance impact while a simple loop would suffice and be faster and more simple.
Recursion is only good if it simplifies your code or your understanding of the concept. the previous example does neither, especially as it does a lot of repetitive things in each iteration, such as asigning the character order constant, rebuilding it into an array and such

For example, the string comparison could be written as such :
function str_compare($a,$b) {
$order="aA??bBcCčČ..."; // longer normally & without that html entities
$default = strlen($a) - strlen($b);
$minlen = strlen($a) < strlen($b) ? strlen($a) : strlen($b);
for ($i = 0; $i < $minlen; $i++) {
$pos_a=strpos($order,$a[$i]);
$pos_b=strpos($order,$b[$i]);
if ($pos_a != $pos_b)
return $pos_a - $pos_b;
}
return $default;
}

Which is much simpler and faster.
Note that the above function will break for characters that are not listed in $order. it should be failry trivial to fix it.

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