[SOLVED] Comparing Objects

[txrandom]

I've got an array of objects that are instantiated based on an ID, but it's possible that multiple objects of the same ID may be added to an array.  I've tried using array_unique to get rid of duplicates, but if the object contains a null data field, it throws some error messages.  How do I get PHP to compare objects by a certain field rather than every variable (null or set) declared in an object?

[Daniel0]

http://php.net/oop5.object-comparison

[Barand]

try

<?php

class txrandom
{
    public $id;
    
    function __construct ($i)
    {
        $this->id = $i;
    }
    
    function __tostring()
    {
        return "$this->id<br>" ;
    }
}

/**
* creating some data 
*/
$txa = array();
for ($i=0; $i<10; $i++)
{
    if ($i==5)
    $txa[] = new txrandom(null);  // throw in a null balue
    else
    $txa[] = new txrandom(rand(1,20));
}

/**
* the processing
*/
sort($txa);                         // if id is first class var, it sorts on that
                                    // otherwise need custom sort with usort()
                                    
foreach ($txa as $obj) echo $obj;   // see what we start with
$prev=-1;
$new = array();
foreach ($txa as $obj) 
{
    if ($obj->id != $prev) $new[] = $obj;           // check for dupe id
    $prev = $obj->id; 
}
echo '<hr>'; 
foreach ($new as $obj) echo $obj;   // see what we end with
?>

[txrandom]

Thanks Barand.  Should array_unique() not be used to remove unique objects? It seems like it's not using tostring() to compare objects.

[Barand]

you said you tried that and it didn't work.

 

PS __tostring() is just to output the object with echo()

[txrandom]

Ahh makes sense. Thanks again.