Alternative for checking the existence of a value in PHP

Question

I'm trying to create a wordpress plugin but checking for the existence of a value doesn't really feel right because there's a bunch of values that I have to check:

$flickr_key = '';
if(!empty($ecom['ecom_options_flickr_api'])){
 $flickr_key = $ecom['ecom_options_flickr_api'];
}
$flickr_secret = '';
if(!empty($ecom['ecom_options_flickr_secret'])){
 $flickr_secret = $ecom['ecom_options_flickr_secret'];
}
$freebase_key = '';
if(!empty($ecom['ecom_options_freebase_api'])){
 $freebase_key = $ecom['ecom_options_freebase_api'];
}
$ebay_key = '';
if(!empty($ecom['ecom_options_ebay_api'])){
 $ebay_key = $ecom['ecom_options_ebay_api'];
}

Is there a more elegant alternative for this?

Answer 1

As Hugo Dozois suggested, using isset with the ternary operator is a good way to do this.

If you can assume that the options have not been set to NULL or false and you can change the $ecom variable you can use array_merge or the union operator.

// Merge with your default values here.
$ecom += array('ecom_options_flickr_api' => '',
 'ecom_options_flickr_secret' => '',
 'ecom_options_freebase_api' => '',
 'ecom_options_ebay_api' => '');
// Set the variables.
$flickr_key = $ecom['ecom_options_flickr_api']; 
$flickr_secret = $ecom['ecom_options_flickr_secret'];
$freebase_key = $ecom['ecom_options_freebase_api'];
$ebay_key = $ecom['ecom_options_ebay_api'];

If they could be NULL or false you could set them using a short ternary as Hugo Dozois mentioned. The indexes will now be set thanks to the union so you won't get Notices for undefined indexes.

Other Suggestions

• I think your structure would be better represented as a multidimensional array:

  $ecom['options'] = array('flickr_api' => '', 'flickr_secret' => 'etc.');

• Often intermediary variables such as $flickr_secret etc. are a bad idea IMO. I prefer to use $ecom['options']['flickr_secret'] in my code. I find aliases normally just confuse the code.

Answer 2

Using ternary operators to removed un-necessary lines

Well you could use the function isset with the use of ternary operators in order to make the code more concise.

I would do the following :

$flickr_key = isset($ecom['ecom_options_flickr_api']) ? $ecom['ecom_options_flickr_api'] : '' ;
$flickr_secret = isset($ecom['ecom_options_flickr_secret']) ? $ecom['ecom_options_flickr_secret']; '';
$freebase_key = isset($ecom['ecom_options_freebase_api']) ? $ecom['ecom_options_freebase_api'] : '';
$ebay_key = isset($ecom['ecom_options_ebay_api']) ? $ecom['ecom_options_ebay_api'] : '';

---

Reducing the code :

Well that is still ugly so you could make a function of it to reduce repetition of the array keys and to have something easier to read.

//You pass the reference of the supposed key
//Since you passe the reference, there will be no notice.
function assign(& $value $default = null){ 
 return isset($value) ? $value : $default;
}
// then use like
$flicker_key = assign($ecom['ecom_options_flickr_api'], '');

For more information see the following Stack Overflow post.

• Wern Ancheta: the second method is nice but I'm still getting notices that the index doesn't exists when I do it.
• Hugo Dozois: @leyasu What version of php are you using? And what do you mean by motices? I've been able to run it just fine on my localhost!
• Wern Ancheta: I'm using PHP version 5.4.9. I'm getting this: Notice: Undefined index: ecom_options_flickr_api
• Peter Kiss: Using ternary operator with array will copy the full array before executing the statement so with a large array it will be slow. With simply ternary operator this code wil give you E_NOTICE if the index doesn't exists no matter what PHP version is it.
• Hugo Dozois: @PeterKiss Alright I've removed the second part, since it was throwing a notice, and that's not clean. Thank you for the feedback