Re: [PHP] Multi-Sort -- how to do this?

tedd wrote:
> Hi gang:
> 
> Here's the problem. Let's say you have a collection of arrays, such as:
> 
> $a = array();
> $b = array();
> $c = array();
> $d = array();
> 
> And then you populate the arrays like so:
> 
> while(...)
>    {
>    $a[] = ...
>    $b[] = ...
>    $c[] = ...
>    $d[] = ...
>    }
> 
> Now, let's say you want to sort the $d array, but you also want the 
> arrays $a, $b, and $c to be arranged in the same resultant order as $d.
> 
> For example, please follow this:
> 
> Before sort of $d:
> $a = [apple, banana, grape, orange]
> $b = [100, 2111, 198, 150]
> $c = [red, yellow, purple, orange]
> $d = [100, 300, 11, 50]
> 
> After sort of $d:
> $a = [grape, orange, apple, banana]
> $b = [198, 150, 100, 2111]
> $c = [purple, orange, red, yellow]
> $d = [11, 50, 100, 300]
> 
> Is there a slick way to do that?

Yes...

<?php

function tedd_sort( &$arrays )
{
     $master = null;
     $followers = array();

     $first = true;
     foreach( array_keys( $arrays ) as $key )
     {
         if( $first )
         {
             $first = false;
             $master = &$arrays[$key];
         }
         else
         {
             $followers[] = &$arrays[$key];
         }
     }


     asort( $master );
     foreach( array_keys( $master ) as $mkey )
     {
         foreach( array_keys( $followers ) as $fkey )
         {
             $value = &$followers[$fkey][$mkey];
             unset( $followers[$fkey][$mkey] );
             $followers[$fkey][$mkey] = &$value;
         }
     }
}

$a = array( 'apple', 'banana', 'grape', 'orange' );
$b = array( 100, 2111, 198, 150 );
$c = array( 'red', 'yellow', 'purple', 'orange' );
$d = array( 100, 300, 11, 50 );

$arrays = array( &$d, &$a, &$b, &$c );
tedd_sort( $arrays );
print_r( $a );
print_r( $b );
print_r( $c );
print_r( $d );

?>

If func_get_args() or func_get_arg() had supported retrieving a 
reference to the argument, then we could have saved having to pass the 
arrays via a combined array. I chose to make $d the first array since in 
your example result set it is the one sorted and thus the rest follow as 
you would expect.

Cheers,
Rob.
-- 
http://www.interjinn.com
Application and Templating Framework for PHP