sorting an associative array of objects by value?

[Greg D]

Hi all,

I'm trying to sort an array of objects within an object. Included is a
dumbed down example so that we can get at the meat of the issue without
worrying about complexity or validation. Basically, Funk is an object that
has a name (string) and a value(int). FunkThis represents an object
containing a list of Funks, with each key corresponding to the name of the
Funk. I want to sort this list by val, but I get a Warning: usort():
Invalid comparison function error when I run the script. Keep in mind that
this is for PHP 4

I'm open to suggestions to getting this to work.



<?php

class Funk {

var $name;
var $val;

function Funk($name,$val ) {
$this->name = $name;
$this->val = $val;
}

function getVal() {
return $this->val;
}

function getName() {
return $this->name;
}
}

class FunkThis {

var $list;

function FunkThis() {
$this->list = null;
}

function add($funk) {
$this->list[$funk->getName()] = $funk;
}

function compareFunks($a ,$b) {
$aVal = $a->getVal();
$bVal = $b->getVal();
if ($aVal == $bVal) return 0;
if ($aVal $bVal) return 1;
if ($aVal < $bVal) return -1;

}

function sortByFunk() {
$list = $this->list;
$this->list = uasort($list,"c ompareFunks");
}

function show() {
print_r($this->list);
}
}

$a = new Funk("A",3);
$b = new Funk("B",7);
$c = new Funk("C",1);
$d = new Funk("D",9);
$e = new Funk("E",6);

$funkthat = new FunkThis();

$funkthat->add($a);
$funkthat->add($b);
$funkthat->add($c);
$funkthat->add($d);
$funkthat->add($e);

$funkthat->sortByFunk() ;

$funkthat->show();
?>

Greg

[Michael Fesser]

Re: sorting an associative array of objects by value?

..oO(Greg D)

>I'm trying to sort an array of objects within an object. Included is a
>dumbed down example so that we can get at the meat of the issue without
>worrying about complexity or validation. Basically, Funk is an object that
>has a name (string) and a value(int). FunkThis represents an object
>containing a list of Funks, with each key corresponding to the name of the
>Funk. I want to sort this list by val, but I get a Warning: usort():
>Invalid comparison function error when I run the script. Keep in mind that
>this is for PHP 4
>[...]

callback

http://www.php.net/manual/en/language.pseudo-types.php#language.types.callback

| A method of an instantiated object is passed as an array containing an
| object as the element with index 0 and a method name as the element
| with index 1.

Since compareFunks() is a method of FunkThis, you need

uasort($list, array($this, 'compareFunks') );

to call it.

Micha

[Greg D]

Re: sorting an associative array of objects by value?


"Michael Fesser" <netizen@gmx.de wrote in message
news:niiun2tqj9 n2rhhf4meql2e95 oau2vinis@4ax.c om...

.oO(Greg D)
>

>>I'm trying to sort an array of objects within an object. Included is a
>>dumbed down example so that we can get at the meat of the issue without
>>worrying about complexity or validation. Basically, Funk is an object
>>that
>>has a name (string) and a value(int). FunkThis represents an object
>>containing a list of Funks, with each key corresponding to the name of the
>>Funk. I want to sort this list by val, but I get a Warning: usort():
>>Invalid comparison function error when I run the script. Keep in mind
>>that
>>this is for PHP 4
>>[...]

>
callback

http://www.php.net/manual/en/language.pseudo-types.php#language.types.callback

>
| A method of an instantiated object is passed as an array containing an
| object as the element with index 0 and a method name as the element
| with index 1.
>
Since compareFunks() is a method of FunkThis, you need
>
uasort($list, array($this, 'compareFunks') );
>
to call it.

Ah, see, I had done that, and when invoking FunkThis->compareFunks() , it
printed 1.

I then used uasort($this->list, array($this, 'compareFunks') );

and it worked fine. Must be because the function parameter is passing the
array by reference.

Thanks!

Greg

[Greg D]

Re: sorting an associative array of objects by value?


"Greg D" <gregd@lasmag.c omwrote in message
news:EZUfh.5656 $a14.2858@newsf e24.lga...

>
"Michael Fesser" <netizen@gmx.de wrote in message
news:niiun2tqj9 n2rhhf4meql2e95 oau2vinis@4ax.c om...

>.oO(Greg D)
>>

>>>I'm trying to sort an array of objects within an object. Included is a
>>>dumbed down example so that we can get at the meat of the issue without
>>>worrying about complexity or validation. Basically, Funk is an object
>>>that
>>>has a name (string) and a value(int). FunkThis represents an object
>>>containing a list of Funks, with each key corresponding to the name of
>>>the
>>>Funk. I want to sort this list by val, but I get a Warning: usort():
>>>Invalid comparison function error when I run the script. Keep in mind
>>>that
>>>this is for PHP 4
>>>[...]

>>
>callback
>http://www.php.net/manual/en/languag...types.callback
>>
>| A method of an instantiated object is passed as an array containing an
>| object as the element with index 0 and a method name as the element
>| with index 1.
>>
>Since compareFunks() is a method of FunkThis, you need
>>
> uasort($list, array($this, 'compareFunks') );
>>
>to call it.

>
Ah, see, I had done that, and when invoking FunkThis->compareFunks() , it
printed 1.
>
I then used uasort($this->list, array($this, 'compareFunks') );
>
and it worked fine. Must be because the function parameter is passing the
array by reference.
>
Thanks!

Actually, that's not quite right either (my bad). I didn't read the
function description fully. uasort affects the array and returns a boolean.
D'oh!

This would do it:

function sortByFunk() {
uasort($this->list, array($this,"co mpareFunks"));
}

and so would this:

function sortByFunk() {
$newlist = $this->list;
uasort($newlist , array($this,"co mpareFunks"));
$this->list = $newlist;
}

What can I say, I'm an idiot. :)

GregoryD