sorting arrays - Sorting an array from outside data

Question

I am attempting to make an ordered array based on an unsorted array from an SQL database.

The data that is gotten from the database will look something like this:

Array (
  //array ('name', position)
  array ('george', 2),
  array ('lenny' , 4),
  array ('rabbit', 1),
  array ('pet'   , 3)
)

The idea is to sort the 'names' in an array where position is there place in the array. What I would like to to end up being:

Array ( 'rabbit', 'george', 'pet', 'lenny' )

The current way I have attempted this is using split_array()

$result is the array from the database.

foreach ( $result as $res ){
  $a = array(array($res['name'], $res['position']));
  array_splice($finalArray, ($res['position'] - 1), 0, $a);
}

The issue is sometimes depending on the order the users are retrieved it will not sort it properly, is there a better way to do this, or is this good and I am doing it wrong? Thanks.

why not sort in the database as part of the query? SELECT name, ord FROM table ORDER BY ord — Aleks G
– Aleks G, Commented Apr 23, 2013 at 8:02
@AleksG Oh yes, I did, it makes my page load MANY times faster! — MichaelMitchell
– MichaelMitchell, Commented Apr 23, 2013 at 8:26

Kovge · Accepted Answer · 2013-04-23 08:46:07Z

Use uasort http://php.net/manual/en/function.uasort.php function where you can pass a user defined comparasion function like this:

$myArray = array(array('bill',3),array('joe',4),array('john',1));

/**
 * @desc compare two arrays by the second element
 * @param array $a (array to compare with an other)
 * @param array $b (array to compare with an other)
 * @return int 0|1|-1 equals|first is bigger|second is bigger
 */ 
function myCompare($a,$b){
    if( $a[1] == $b[1] ){
        return 0;        //if the 2nd elements equals return 0
    }
    return ( $a[1] > $b[1] )?1:-1;  //if the 2nd element of the 1st parameters is bigger returns 1 , else returns -1
}

Usage:

uasort( $myArray, 'myCompare' );

The uasort manipolates the original array in place.

Result:

 var_dump($myArray);

 array(
       array('john',1),
       array('bill',3),
       array('joe',4)
 );

Recommendation:

If you could edit the SQL query , better to short the results in the query with ORDER BY directive like this:

 SELECT `name`,`position` 
 FROM `mytable`  #your table name
 WHERE 1  #or your conditions here
 ORDER BY `position` ASC  #ordering directive

This should run faster. And if use this, recommend to add index to position field.

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