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1

** EDIT ** What would happen if I only used arrays, e.g.

array( array('name' => 'bla', 'distance' => '123'); array('name' => 'b123a', 'distance' => '1234214'); );

Would this be easier to find the min value ?

Hi there I'm trying to retrieve the object which has the lowest distance value from an array of objects. This is my data set below;

    [0] => myObjectThing Object
        (
            [name:myObjectThing:private] => asadasd
            [distance:myObjectThinge:private] => 0.9826368952306
        )

    [1] => myObjectThing Object
        (
            [name:myObjectThing:private] => 214gerwert24
            [distance:myObjectThinge:private] => 1.5212312547306
        )

    [2] => myObjectThing Object
        (
            [name:myObjectThing:private] => abc123
            [distance:myObjectThinge:private] => 0.0000368952306
        )

So I'd like to be able to retieve the object which has the smallest distance value. In this case it would be object with name: abc123

Thanks in advance for your help

Andy

share|improve this question
 
"What would happen if I only used arrays?" - you could then array_multisort (au2.php.net/manual/en/function.array-multisort.php). But it wouldn't make a bug difference in this case because you can just use array_walk –  xzyfer Mar 2 '11 at 11:18
1  
you don't need to type "please vote my question" –  llnk Mar 2 '11 at 11:19
 
I'd say the question has managed to stir a good debate, that was all. I've removed now, sorry –  Garbit Mar 2 '11 at 11:21
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6 Answers

up vote 1 down vote

Hmm for PHP >= 5.3 I would try something like this:

$Object = array_reduce($data,function($A,$B){
    return $A->distance < $B->distance ? $A : $B;
})

For PHP < 5.3 the fillowing would suffice:

function user_defined_reduce($A,$B){
    return $A->distance < $B->distance ? $A : $B;
}
$Object = array_reduce($data,"user_defined_reduce");
share|improve this answer
 
thats what you call concise :) –  Garbit Mar 2 '11 at 11:18
 
Thanks, Small but effective. –  RobertPitt Mar 2 '11 at 11:21
 
+1 This is what I was going for, stupid me forgot about array_reduce. FYI, he wants to return the object. –  xzyfer Mar 2 '11 at 11:22
 
Works only for PHP 5.3 and above. Care to add version for older PHP? –  Kamil Szot Mar 3 '11 at 10:13
 
Added a version for PHP < 5.3 –  RobertPitt Mar 3 '11 at 10:47
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up vote 1 down vote

Previously suggested answers did not explain the need to include an $initial value to array_reduce(). The solution did not work because of it.

This one works for me (PHP 5.3.13):

$array = array(
    array(
        'name' => 'something',
        'value' => 56
    ),
    array(
        'name' => 'else',
        'value' => 54
    ),
    array(
        'name' => 'else',
        'value' => 58
    ),
    array(
        'name' => 'else',
        'value' => 78
    )
);
$object = array_reduce($array, function($a, $b){
    return $a['value'] < $b['value'] ? $a : $b;
}, array_shift($array));

print_r($object);

This will give me:

[0] => Array
(
    [name] => else
    [value] => 54
)

Whereas the previous solution gave me null. I'm assuming that PHP < 5.3 would require a similar initial value to be specified to array_reduce().

share|improve this answer
 
If you're looking for a minimum value with array_reduce in unsorted array, I think there's a chance you won't get the minimum value? –  Dalius Aug 6 '13 at 14:10
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up vote 0 down vote

You can't flatten this as it isn't a plain old multi-dimensional array with just the values.

This should work:

$min = $object[0];
for ($i = 1; $i < count($object); $i++)
    if ($object[$i]['distance'] < $min['distance'])
        $min = $object[$i];
share|improve this answer
 
And which object has the minimal value ? You didn't got it - just minimal value. –  hsz Mar 2 '11 at 11:08
 
Thanks for that, I've fixed it. –  Delan Azabani Mar 2 '11 at 11:09
 
If I didn't use objects and just had a massive array would this be easier? Only problem with doing it with a big array is that it's a bit hacky. My only problem with using another loop is that I am already at O(n^2) which will be huge if i wrap another loop in there –  Garbit Mar 2 '11 at 11:11
 
Would it be possible to integrate it into your main loop to avoid pushing past O(n)? Or is your main loop not through the objects? –  Delan Azabani Mar 2 '11 at 11:17
 
It's through another data set, so i'm pulling data then for each element im then making another request for that data. If i added another loop within this i think it would be too cumbersome –  Garbit Mar 2 '11 at 11:20
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up vote 0 down vote

This example should give you a hint in the right direction:

<?php

$a = new stdClass();
$a->foo = 2;
$b = new stdClass();
$b->foo = 3;
$c = new stdClass();
$c->foo = 1;

$init = new stdClass();
$init->foo = 1000;

$vals = array( $a, $b, $c );

var_dump(
    array_reduce(
        $vals,
        function ( $x, $y )
        {
            if ( $x->foo < $y->foo )
            {
                return $x;
            }   
            else
            {
                return $y;
            }   
        },  
        $init
    )   
);  

?>
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up vote 0 down vote

try:

$myObjectCollection = ...;
$minObject = $myObjectCollection[0]; // or reset($myObjectCollection) if you can't ensure  numeric 0 index

array_walk($myObjectCollection, function($object) use ($minObject) { 
        $minObject = $object->distance < $minObject->distance ? $object : $minObject;
});

but from the looks of your dump. name and distance are private. So you want be able to access them from the object directly using ->. You'll need some kind of getter getDistance()

share|improve this answer
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up vote 0 down vote 
$objectsArray = array(...); // your objects
$distance     = null;
$matchedObj   = null;

foreach ( $objectsArray as $obj ) {
   if ( is_null($distance) || ( $obj->distance < $distance ) ) {
      $distance   = $obj->distance;
      $matchedObj = $obj;
   }
}

var_dump($matchedObj);

AD EDIT:

If you will use arrays instead of objects, change $obj->distance to $obj['distance'].

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