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up vote 1 down vote favorite

Possible Duplicate:
How to use an object method as a callback function

Usually I used array_map with procedural code, but in this case I'm working in OOP and the callback should be "this->id2areas", but It's not working. Is there anyway of put this callback with OOP?

ERROR MESSAGE: array_map() expects parameter 1 to be a valid callback, function 'this->id2area' not found or invalid function name

MY CODE =================================================================================

$this->context->assign('user_areas', implode(', ', array_map('id2area',   explode(',', $this->user['areas']))));     
explode(',', $this->user['areas']))));



function id2area($id) {//callback
    if ($id == 0) {
        return 'National';
    }
    $query = "SELECT area FROM area WHERE id = $id";
    return DB::fetch_instance()->slave->fetchColumn($query);
}
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marked as duplicate by Gordon, PeeHaa, tereško, markus, Kevin Nov 13 '12 at 0:21

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
up vote 9 down vote accepted

In PHP, you can use an array to associate an object and a method call as a callable

array_map(array($this, 'id2area'), $array);

http://php.net/manual/en/language.types.callable.php

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2  
And, since id2area() doesn't actually use the $this instance context, I would recommend making it a static function. Then referenced as array_map(array('className','id2area'), $array) – Michael Berkowski Nov 12 '12 at 17:20
    
@MichaelBerkowski Or in most cases, array(__CLASS__, 'id2area') :) – Ja͢ck Nov 12 '12 at 17:22
up vote 6 down vote

PHP callbacks for objects is a bit different then global functions.

//Global function callback
array_map('id2area', $data);

// Object function
array_map(array($object, 'id2area'), $data)
// - or -
array_map(array($this, 'id2area'), $data)

// Static class function
array_map(array('Class_Name', 'id2area'), $data)
// - or -
array_map('Class_Name::id2area', $data)

http://us1.php.net/manual/en/language.types.callable.php

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up vote 3 down vote

You could also do this as an anonymous function like:

array_map(
    function($arg) {
        return $this->id2area($arg);
    },
    explode(',', $this->user['areas'])
);
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