如何在数组中循环并使用if语句中的每个值

I have the function:

public function onK2AfterDisplayContent(&$item,&$params,$limitstart)
{   
    $cat_id = $this->params['cat_ids'];
    explode(',', $cat_id);

    $view = JRequest::getVar('view');

    if($view === 'item' && $item->catid === $cat_id){
        $db = JFactory::getDbo();
        $query = 'SELECT name FROM #__k2_categories WHERE id='.$item->catid;
        $db->setQuery($query);
        $resultado = $db->loadResult();

        echo '<input class="subscribete" type="button" id="'.$resultado.'-'.$item->id.'" value="Subscribete" data-id="'.$item->id.'"/>';    
    }
}

The variable $cat_id can bring a different amount of values (1 or 1,2,3, nothing, etc..). My if statement should only enter when one of these values exist in $item->catid. How can I accomplish this?

EDIT: $item->catid can only be a single value like "1".

You can use in_array :

$cat_id = explode(',', $this->params['cat_ids']);
// Don't forget to assign the explode to a value. Otherwise, it won't be usefull...

if (in_array($item->catid, $cat_id)) {
    // Do something
}

First, you aren't assigning the explode to anything, so nothing changes in that bit of code:

explode(',', $cat_id);

Secondly, if you do assign it, you can then do a simple foreach statement to poke through each bit of data that comes out.

public function onK2AfterDisplayContent(&$item,&$params,$limitstart)
{   
    $cat_id = $this->params['cat_ids'];
    $carArr=explode(',', $cat_id);

    $view = JRequest::getVar('view');

    foreach($catArr as $val)
    {
        if($view == 'item' && $item->catid == $cat_id){
        $db = JFactory::getDbo();
        $query = 'SELECT name FROM #__k2_categories WHERE id='.$item->catid;
        $db->setQuery($query);
        $resultado = $db->loadResult();

        echo '<input class="subscribete" type="button" id="'.$resultado.'-'.$item->id.'" value="Subscribete" data-id="'.$item->id.'"/>';    

    }

    }
}

Edit: After posting, I noticed John's answer about the === operator, which I think might also cause issues - I didn't even notice it first time round, so have changed it to a == instead.