Question

I need to selectively flatten an array in PHP, but do it selectively. If a key matches a pattern then all sub elements below that key should be included in the ‘flat’ output.

SO If I had a catalogue of music:

=> array of albums => each of which is an array of song titles

Then I could search for a string, and would get a flat array in reponse. SO if I searched for ‘sun’ then I would get the entire catalogue for any artist with ‘sun’ in their name, plus the albums for other artists where ‘sun’ was in the album name.

Hopefully that makes sense.

Anyone got any thoughts?

Answer 1

Ok, I’m going to assume your data looks like this:

$data = array(
    "Bill Withers" => array (
        "Lovely Day",
        "Use Me",
        "Ain't No Sunshine"
    ),
    "Fleet Foxes" => array (
        "Sun It Rises",
        "White Winter Hymnal"
    ),
    "Billy Joel" => array (
        "Piano Man"
    )
);

…and that given the input "Bill", you want the output: ["Lovely Day", "Use Me", "Ain't No Sunshine", "Piano Man"]. Here’s one way you could do it.

function getSongs($data, $searchTerm) {
    $output = array();
    foreach ($data as $artist => $songs) {
        if (stripos($artist, $searchTerm) !== false)) {
            $output = array_merge($output, $songs);
        }
    }
    return $output;
}

…I’ll also assume you’ve got a good reason to not use a database for this.