up vote 6 down vote favorite
1

(array)$someemptyvariablethatisnotarray returns array([0] =>) instead of array()

How can I make it so I get a empty array that is not iterated when I'm using it inside foreach() ?

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2  
When you use var_dump() instead of print_r() it shows you also the type of the value in the array! – powtac Mar 24 '11 at 15:37

7 Answers

up vote 11 down vote accepted

The feature which you are using, is called "casting". This means a variable is forced to become a given type, in your example an array. How the var is converted is not always obvious in PHP!

In your example $someemptyvariablethatisnotarray becomes an array with one entry with a NULL value.

The PHP documentation says:

The behaviour of an automatic conversion to array is currently undefined.

To solve your code I would recommend something like this:

if (!is_array($someemptyvariablethatisnotarray) {
    $someemptyvariablethatisnotarray = array();
}
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1  
php.net/manual/en/… – Rocket Hazmat Mar 24 '11 at 15:34
1  
If you casted NULL as an array, it would become a blank array, if you cast a scalar value (even an empty string, because that's not NULL) it becomes an array with that value, not a NULL value. – Rocket Hazmat Mar 24 '11 at 15:36
up vote 7 down vote 
$var = array();

will empty an array. Is this what you're after?

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up vote 3 down vote 
if(!$variable){
        return array();
}
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up vote 2 down vote 
$somevar = empty($somevar) ? array() : (array)$somevar;

Maybe? Though I'm not sure I get the cast, or the purpose. Care to ellaborate a bit more (maybe an example of what you're trying to accomplish?)

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I'm using it like foreach((array)$something as $k).... Sometimes $something may be "false" and not a array, so I don't want foreach to iterate it – Alex Mar 24 '11 at 15:23
@Alexandra: I know PHP's flexible, but if you're finding your variables switching datatypes on you, there should be a check somewhere else to catch that (don't rely on a cast in other words). I'm going to jump the gun and assume it's database related, and a fetch row which could potentially return a FALSE which would inhibit you iterating over the elements, correct? – Brad Christie Mar 24 '11 at 15:31
yes :) I hate making checks for every small thing, but I guess I have no choice here.. – Alex Mar 24 '11 at 15:33
@Alexandra: I might advise while (($row = mysql_fetch_array($result)) !== false){ ... }. That's still a "check". ;-) – Brad Christie Mar 24 '11 at 15:35
up vote 2 down vote

Try unset($someemptyvariablethatisnotarray[0]) :)

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up vote 2 down vote

how are you?

I believe this is what you're after:

$something = false;
foreach((array)(empty($something) ? null : $something) as $k){
    echo 'never enters here';
}

You don't get an empty array, because when you set "(array)false", it means you'll have a single element, and that element will have the "FALSE" value assigned to it.

Same happens with an empty string (not a null one!) (array)$emptystring will return an array which contains a single element, which is an empty string!

Similar to doing:

array('');

Hope it helps.

Cheers!

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up vote 1 down vote

When you cast a non-array as an array, it creates an array with that variable as the only value.

If you want an empty array, you need to return array().

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