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"PHP Sorting a array"

rik wrote:
> in Perl you use = for equals in number comparisons

nearly, you use == for numerical comparison. = is used to set a variable or array etc...

as for custom sort operations, i think you might be correct. the function you want is: usort()

ive never used it before, but here is the example from the PHP manual:

function cmp ($a, $b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}

$a = array (3, 2, 5, 6, 1);

usort ($a, "cmp");

while (list ($key, $value) = each ($a)) {
echo "$key: $value\n";
}

-----------------

ur definitely correct about splitting it around the #. try this:

for ($i=0; $i<=count($blah); $i++)
{ $blah2[$i] = explode("#", $blah[$i]); }

// you can then call the number using $blah[$i][0] i believe

Nimco wrote:
> rik wrote:
> in Perl you use = for equals in number comparisons
>
> nearly, you use == for numerical comparison. = is used to set a
> variable or array etc...

Yeh, mistype :-) You can check those minor details as you code ;-)

> as for custom sort operations, i think you might be correct. the
> function you want is: usort()
>
> ive never used it before, but here is the example from the PHP
> manual:
>
> function cmp ($a, $b) {
> if ($a == $b) return 0;
> return ($a $b) ? -1 : 1;
> }
>
> $a = array (3, 2, 5, 6, 1);
>
> usort ($a, "cmp");
>
> while (list ($key, $value) = each ($a)) {
> echo "$key: $value\n";
> }
>
> -----------------
>
> ur definitely correct about splitting it around the #. try this:
>
> for ($i=0; $i<=count($blah); $i++)
> { $blah2[$i] = explode("#", $blah[$i]); }
>
> // you can then call the number using $blah[$i][0] i believe

Yup, the OP just needs to combine those two things to create his custom function, which explodes his array value, then compares the numbers and returns appropriately.

Rikki

Rikki wrote:
> Yup, the OP just needs to combine those two things to create his
> custom function, which explodes his array value, then compares the
> numbers and returns appropriately.
>
> Rikki

I think the problem he is gonna have is that when you split a string, it returns strings. this means that it will not sort them numerically, but literally, thus it would think for example: 3 > 100 since 3 > 1.

to avoid this, use settype(), e.g. settype($blah[$i], "int");

:)

Seems to be a much simpler solution to this.

sort($blah,SORT_NUMERIC);

Just tried it on the test data given and it does produce

blah[0]=3#moo
blah[1]=43#blah
blah[2]=60#cough
blah[3]=100#woof

It works because of how PHPs (and PERLs for that matter) string->number conversion behaves. Typically, it looks at the string and just keeps reading numbers until it encounters the end or a non numeric character hence "3#moo" -> 3 and so on..

A more general point, don't be so caught up in trying to solve things with php functions. They are there for convenience but they aren't the beginning and the end of the language by a long way. You all seem to have expended alot of effort trying to use builtin functions when you could of written the code yourselves in 6 lines (a simple sort routine is nothing fancy, 2 nested for loops and a comparison in the middle).

-G

Aren't the built-in sort routines faster and more optimized than one you'd write yourself. To start with, you'd have to pick the best sort for your own function (bubble, quick, whatever else you can think of), and try and make it as quick as possible, where as the built-in sort is all done for you. Agreed there's some things easier to do yourself than search the tons of built-in functions for what you want, but surely sort is one you should leave to the built-ins...?

Rikki