Every third element should have a date beside it - php

Question

So I have been asking a lot of array based questions as I strive to understand PHP's main source of data structure.
I am currently working on building a class that spits out a list of artists and their songs. each third song has a date beside it. as seen in this array:
$music = array(
'Creed' => array(
'Human Clay' => array(
array(
'title' => 'Are You Ready'
),
array(
'title' => 'What If'
),
array(
'title' => 'Beautiful',
'date' => '2012'
),
array(
'title' => 'Say I'
),
array(
'title' => 'Wrong Way'
),
array(
'title' => 'Faceless Man',
'date' => '2013'
),
array(
'title' => 'Never Die'
),
array(
'title' => 'With Arms Wide pen'
),
array(
'title' => 'Higher',
'date' => '1988'
),
array(
'title' => 'Was Away Those Years'
),
array(
'title' => 'Inside Us All'
),
array(
'title' => 'Track 12',
'date' => '1965'
),
),
),
);
What I wrote was the following:
class Music{
protected $_music = array();
protected $_html = '';
public function __construct(array $music){
$this->_music = $music;
}
public function get_music(){
$year = '';
$this->_html .= '<d1>';
foreach($this->_music as $artist=>$album){
$this->_html .= '<dt>' . $artist . '</dt>';
foreach($album as $track=>$song){
foreach($song as $songTitle){
if(isset($songTitle['date']) && !empty($songTitle['date'])){
$year = '['.$songTitle['date'].']';
}
$this->_html .= '<dd>' . $songTitle['title'] . $year. '</dd>';
}
}
}
$this->_html .= '</d1>';
}
public function __toString(){
return $this->_html;
}
}
$object = new Music($music);
$object->get_music();
echo $object;
My question is that I end up getting something back that looks like this:
Creed
Are You Ready
What If
Beautiful[2012]
Say I[2012]
Wrong Way[2012]
Faceless Man[2013]
Never Die[2013]
With Arms Wide pen[2013]
Higher[1988]
Was Away Those Years[1988]
Inside Us All[1988]
Track 12[1965]
As you can see almost every song has a date beside it when in the array that is not the case. My question is whats the deal? I thought in my loop I was very clear in stating if this song has a year, set it and then print it beside the song title?
Can some one point me in the right direction please?

Answer 1

When the date is not set for a song, the year variable is holding the value from the previous song (for which it was set). You are still actually telling it to print year next to the title, whether or not the date is set.
You need an else clause on the if:
if(isset($songTitle['date']) && !empty($songTitle['date'])){
$year = '['.$songTitle['date'].']';
} else {
$year = '';
}
This will clear out year when the date is not set.

Answer 2

You never reset $year after you set it, so once you encounter the first year value in your array, you'll be constantly using that same year until a new one comes along:
if(isset($songTitle['date']) && !empty($songTitle['date'])){
$year = '['.$songTitle['date'].']';
} else {
$year = ''; /// reset year to blank
}
And in somewhat unrelated stuff, this is probably a typo:
$this->_html .= '<d1>';
^--- number one? not letter L for a `<dl>` tag?

Answer 3

You are not resetting year in foreach loop, so it is using last set year until value is reassigned. Here is corrected Music class.
class Music{
protected $_music = array();
protected $_html = '';
public function __construct(array $music){
$this->_music = $music;
}
public function get_music(){
$year = '';
$this->_html .= '<d1>';
foreach($this->_music as $artist=>$album){
$this->_html .= '<dt>' . $artist . '</dt>';
foreach($album as $track=>$song){
foreach($song as $songTitle){
if(isset($songTitle['date']) && !empty($songTitle['date'])){
$year = '['.$songTitle['date'].']';
}
$this->_html .= '<dd>' . $songTitle['title'] . $year. '</dd>';
$year = "";
}
}
}
$this->_html .= '</d1>';
}
public function __toString(){
return $this->_html;
}
}