What's wrong with my PHP array?

Question

    $genreList;

    function directorGen($array)
    {
     foreach($array as $value)
        {
    $genreList[] = $value; 
     }
    }

   //later..

   directorGen($title->genres());

This code results in a NULL array. If I replace $genreList[] = $value with echo $value everything prints out like expected. Any ideas?

Answer 1

Where is $genreList defined? It may just be a function-local variable, in which case it's lost when the function exits. If it's a class-level variable, remember to use $this->genreList instead.

Edit

My mistake. If it's a global variable, you need to add this to the top of the function in order for PHP to find it:

global $genreList;

Answer 2

It's a scope issue. The $genreList within directorGen() only exists within directorGen(), it's not implicitly a global just because it was mentioned outside the function. Try using global $genreList at the top of the function.

Answer 3

Either of the following should fix your problem;

$genreList[] .= $value; // Appends each value to the array. 

array_push($genreList, $value);

Also my mistake, you should be returning the genreList from the function via this statement:

return $genreList;

Using the global keyword is generally considered a code smell as it can create numerous issues in tracking the usage of the global variable as well as its value as it changes.

Answer 4

If $genreList is a global variable, there's your problem: it's a scope issue. It can easily be fixed with:

$genreList = array();

function directorGen($array) {
    global $genreList;
    foreach($array as $value) {
        $genreList[] = $value;        
    }
}

Note: while not strictly necessary I also initialized it, which I think is good practice.

If directorGen() is a member function and $genreList is a data member then change to:

function directorGen($array) {
    foreach($array as $value) {
        $this->genreList[] = $value;        
    }
}

Answer 5

function directorGen($array)
{
    $genreList = array();

    foreach($array as $value)
    {
        $genreList[] = $value;        
    }

    return $genreList;
}

//later..

directorGen($title->genres());

You will always receive array. Even it is empty. And you not need to check it with is_array() function.

Answer 6

This is probably what you want to do:

class Test {
    //public, protected, private ...
    var $genreList = array();

    function directorGen(array $array) {
     //remove string keys
     $values = array_values($array);
     $this->genreList = array_merge($this->genreList, $values);
    }
}

NB: Will reset the counters. If you unset a value and then add new values, the keys will be reset with lowest at 0 and max at count - 1.