Looping and comparing objects

I have two arrays of objects,

They are identical except one has more items,

so they would look like

Array [arrayA]
(
    [0] => stdClass Object
        (
            [id] => 2
            [name] => interest 1
            [description] => interest one
        )

    [1] => stdClass Object
        (
            [id] => 4
            [name] => interest 3
            [description] => interest three
        )

)



Array [arrayB]
(
    [0] => stdClass Object
        (
            [id] => 1
            [name] => all
            [description] => everything
        )

    [1] => stdClass Object
        (
            [id] => 2
            [name] => interest 1
            [description] => interest one
        )

    [2] => stdClass Object
        (
            [id] => 4
            [name] => interest 3
            [description] => interest three
        )

    [3] => stdClass Object
        (
            [id] => 5
            [name] => interest 4
            [description] => interest four
        )

)

Now what I want to do is, loop over arrayB, if the object is found in arra开发者_开发知识库yA (maybe compare the ID?) then set [checked] => true else set [checked] = false on arrayB.

What is the easiest way to do this?

I have thought of doing maybe

foreach($arrayB as &$obj){
    $obj->checked = false;
    foreach($arrayA as $obja){
        if($obja->id == $obj->id){
            $obj->checked = true;
            break;
        }
        if($obja->id > $obj->id) //thanks to De3pTh0ught
            break;
    }
}

But there has to be a more efficient way?

You could add a check to cut useless iterations. If you know that the object IDs in your arrays will always be in increasing order, you could include the condition: if $obja's ID is greater than $obj's ID, then break $arrayA's foreach loop, because that means that $obj will never find a match.

This can be done with this horrible hack (in 2 lines!):

$p = print_r($arrayA, true);
foreach($arrayB as &$o) $o->checked =substr_count($p, "[id] => {$o->id}\n") == 1;

After some thought about how inefficient substr_count could be - think of its internal implementation; it cannot be very efficient - I came up with a slightly different method:

$b = print_r($arrayA, true);
foreach($arrayB as &$o) 
     $o->checked = strpos($b, "[id] => {$o->id}" . PHP_EOL, 60) !== false;