Complex & Confusing PHP Array Calculations

Question

I have set of data that I need help with. I need to make a difficult calculation and array sort through several multidimensional arrays and the logic and syntax is giving me a headache.

Basically what I need it:

• an array of keywords
• I need to query a database and store some results for each keyword. (ID and Count of keyword matches)
• I need to then flip the array around so instead of keywords being the parent element, it's IDs with the count of matches for each keyword within
• I need to perform a calculation to get a single number from these number of matches
• I need to sort the array so I can see which ID yielded the highest match value in the database, so I can query and output the relevant data.

I know how I am going to do the calculation for the relevancy now, it's just I've only briefly worked with single dimension arrays and I don't know how to syntactically represent what I need with this example. Could anyone give me a hand?

Here is a sample of what I want - not sure if this is syntactically the best way to show you, but hopefully you'll get the picture:

Array
    (
        [Keywords] => Array
        (
            ["wax"] => Array
            (
                [ID] => 1
                [Match] => 8

                [ID] => 2
                [Match] => 10
            )
            ["hard"] => Array
            (
                [ID] => 1
                [Match] => 2

                [ID] => 2
                [Match] => 37
            )
        )

Then this array would need to be translated to:

Array
    (
        [ID] => Array
        (
            ["1"] => Array
            (
                [Keyword] => "wax"
                [Match] => 8

                [Keyword] => "hard"
                [Match] => 10
            )
            ["2"] => Array
            (
                [Keyword] => "wax"
                [Match] => 2

                [Keyword] => "hard"
                [Match] => 37
            )
        )    

Answer 1

This code:

$arr =  array
        (
            "wax" => array
            (
                array(
                    'ID' => 11,
                    'Match' => 8
                ),
                array(
                    'ID' => 21,
                    'Match' => 10
                )
            ),
            "hard" => array
            (
                array(
                    'ID' => 11,
                    'Match' => 2
                ),
                array(
                    'ID' => 21,
                    'Match' => 37
                )
            )
        );

$byid = array();
foreach($arr as $kw => $res) {
    foreach($res as $r) {
        $byid[$r['ID']][] = array('Keyword' => $kw, 'Match' => $r['Match']);
    }
}

var_export($byid);

gives:

array (
    11 => 
        array (
            0 => 
                array (
                    'Keyword' => 'wax',
                    'Match' => 8,
                ),
            1 => 
                array (
                    'Keyword' => 'hard',
                    'Match' => 2,
                ),
        ),
    21 => 
        array (
            0 => 
                array (
                    'Keyword' => 'wax',
                    'Match' => 10,
                ),
            1 => 
                array (
                    'Keyword' => 'hard',
                    'Match' => 37,
                ),
        ),
)

I hope it helps.

Answer 2

You can query the db and create both the arrays by,

$query = "select id, keyword, count(*) as keyword_count from [your table] group by keyword";
$result = mysql_query($query);
while($row = mysql_fetch_array($result)){
  $keyword = $row['keyword'];
  $id = $row['id'];
  $count = $row['keyword_count'];
  $first_array["keywords"]["$keyword"] = array('id' => $id, 'match' => $count);
  $second_array["id"]["$id"] = array('keyword' => $keyword, 'match' => $count);
}
print_r($first_array);
print_r($second_array);