[Resolved] sorting email addresses

[kemu_]

I have tried to sort a array which has the name-part of email address, but with no luck so far. So what am i doing wrong?

$names is an array which contains the addresses in format "firstname.lastname"

i use my own sort-function to sort the array, but it doesnt work right.

function sort_name($b,$a) {  

	$a = explode(".",$a);
	$b = explode(".",$b);
	return(!strcasecmp ($a[1],$b[1]));
}

usort($names,sort_name);
echo implode($names,"<br>");

and it still shows the names in their original order....

so what is wrong there? Prolly some small prob, but i cant seem to notice it :S

[Weedpacket]

You want your function to return a value <0 if $a comes before $b, ==0 if $a is the same as $b, and >0 if $a comes after $b. strcasecmp() produces such a value.

But with that ! there all you're returning is true (if they are the same) or false (if they are different). On top of that, true is equivalent to 1 and false is equivalent to 0.

So if two emails have different last names, your function is telling usort() that they are the same; and if they're the same, you're saying that the first one is bigger.

As a result, nothing gets sorted.

Practical upshot, remove the ! and just return the results from strcasecmp (which are already of the correct form).

Oh, and incidentally, it should be usort($names, 'sort_name'); and unless you want the array to be in reverse order, sort_name($a,$b) would have a better effect.

[kemu_]

That solved it, thx....
the reason i had the ! before strcasecmp because it sorted them in wrong order, and i wisely thought that would fix it.... d'oh... swapping $a and $b (dunno why i actually had them in that order) and the ! fixed the sorting right..