在关联数组中插入值，但仅在有值时插入

I've this bucle:

foreach($jsonU as $j) {
        $jsonUId = $j->id;
        $jsonUName = $j->name;
        $jsonUDescription = $j->description;
        $jsonUDate = $j->date;
        $jsonUStatus = $j->status;
        $jsonUPicture = $j->picture;

        $jsonUncompleted[] = array('id'=> $jsonUId, 'name'=> $jsonUName, 'description' => $jsonUDescription, 'date' => $jsonUDate, 'status' => $jsonUStatus, 'picture' =>$jsonUPicture);
}  

I need to insert a key in the array only if have value. For example, $jsonUPictore not always has a value and in that case I don't need to write that key.

Some help?

You could use the array_filter function with or without a parameter:

http://www.php.net/manual/en/function.array-filter.php

Example:

$jsonUncompleted[] = array_filter( array(
  'id'=> $jsonUId, 'name'=> $jsonUName, 'description' => $jsonUDescription,
  'date' => $jsonUDate, 'status' => $jsonUStatus, 'picture' =>$jsonUPicture
));

If you are wanting to remove all NULL values from an array there's an easy way to do it using the array_filter function the last poster mentioned:

$new_array_without_nulls = array_filter($array_with_nulls, 'strlen');

Source: http://briancray.com/posts/remove-null-values-php-arrays/