[RESOLVED] Multidimensional Array Sorting

[phattymatty]

I'm having some trouble sorting a multidimensional array I have created. The use of this sorting is to set up "standings", sorted by WINS descending, LOSSES ascending, and TIES descending. The array looks as such:

$teams = Array ( [21] => Array ( [name] => Whitesox [wins] => 8 [losses] => 5 [ties] => 1 ) [20] => Array ( [name] => Yankees [losses] => 10 [wins] => 3 [ties] => 1 ) [22] => Array ( [name] => Cardinals [losses] => 12 [wins] => 2 ) [23] => Array ( [name] => Reds [wins] => 11 [losses] => 1 [ties] => 1 ) [24] => Array ( [name] => Rangers [wins] => 11 [ties] => 1 [losses] => 1 ) [25] => Array ( [name] => Redsox [losses] => 9 [wins] => 3 [ties] => 2 ) );

//This array is dynamically created based on inputted game scores

I tried tinkering with user defined sorts.... these were what I tried::

function comparewins($x, $y)
{	//This is supposed to help us sort our array below by wins descending
if ( $x['wins'] == $y['wins'] )
 return 0;
else if ( $x['wins'] < $y['wins'] )
 return -1;
else
 return 1;
}
function comparelosses($x, $y)
{	//This is supposed to help us sort our array below by losses ascending
if ( $x['losses'] == $y['losses'] )
 return 0;
else if ( $x['losses'] < $y['losses'] )
 return 1;
else
 return 1;
}
function compareties($x, $y)
{	//This is supposed to help us sort our array below by ties descending
if ( $x['ties'] == $y['ties'] )
 return 0;
else if ( $x['ties'] < $y['ties'] )
 return -1;
else
 return 1;
}

And I tried applying them as such:

//Sort the results of the array by wins DESC, losses ASC, ties ASC, ((losses + wins + ties) / (wins +.001 + .5*ties)) ASC
	usort($teams, 'comparewins');
	usort($teams, 'comparelosses');
	usort($teams, 'compareties');

Needless to say, the sort did not work. I have tried a number of ideas with no luck. The only other idea I have is to send the results back to mysql and store the # of wins/losses/ties that way and then use mysql sort attributes to get the data sorted as needed.

Assuming I get this data sorted, then I will need to display it. Previously, I used the while ($row =mysql_fetch_assoc) loop to get through the sorted sql array. Here was that code:

<?php 
$sql =	"SELECT *  

			FROM teams
			WHERE division = '$division'		
			ORDER BY wins DESC, losses ASC, ties ASC, ((losses + wins + ties) / (wins +.001 + .5*ties)) ASC";
	$result = mysql_query($sql);
	$row = mysql_fetch_assoc($result);
	$maxwins = $row['wins'];
	if (!$result) 
	{
		echo "Error running query ($sql) for Standings: " . mysql_error();
		exit;
	} 	
 ?>
<table class="tables">
  <tr class="column_names">
    <td class="first">&nbsp;</td>
	<td>Team</td>
    <td>Wins</td>
    <td>Loss</td>
    <td>Tie</td>
	<td>PCT</td>
    <td>Games Back</td>
    <td>Runs Allowed</td>
    <td>Runs Scored</td>
	<td class="last">Run Ratio</td>
  </tr>
  <?php $position = 0; 
   while ($row = mysql_fetch_assoc($result)){?>
  <tr>
    <td class="first"><?php $position = $position + 1; echo $position."."; ?></td>
	<td><?php echo ucwords($row['name']); ?></td>
    <td><?php echo $row['wins']; ?></td>
    <td><?php echo $row['losses']; ?></td>
	<td><?php echo $row['ties']; ?></td>
    <td><?php $wins = $row['wins'] + .5*$row['ties']; $losses = $row['losses'] + .5*$row['ties']; $tot= $wins + $losses; if ($tot != 0){$pct = $wins / $tot; printf("%0.3f", $pct); }?></td>
    <td><?php $gb = $maxwins - (.5*$row['ties']) - $row['wins']; if ($gb <= "0"){$gb = "-"; }echo $gb; ?></td>
    <td><?php $runs_allowed = get_runs_allowed(addslashes($row['name']), $division); echo $runs_allowed; ?></td>
    <td><?php $runs_scored = get_runs_scored(addslashes($row['name']), $division); echo $runs_scored; ?></td>
	<td class="last"><?php if($runs_scored != "0" || $runs_allowed != "0"){$run_ratio = $runs_scored / $runs_allowed; printf("%0.3f", $run_ratio);}else{printf("%0.3f", 0);} ?>
  </tr>
  <?php } ?>
</table><?php 
}

How would I set up the same type of loop using the multidimensional array I have created. I thought about using a foreach but I got confused.

If I use a for each then how do I add more functions such as total runs scored, runs allowed, and the run ratio AND calculate other variables such as games back, win pct,. Wouldnt the foreach end after it looped through the array? This data is not provided in the array but returned from another function(s).

NOTE: My array takes the form: $teams['dynamicallygeneratedfromtheirteamid']['wins...losses...etc'].
I don't understand how to loop through $teams without knowing which team id is set after sorted.

Thanks for any help folks. I really appreciate it!

[NogDog]

Is this what you want?

<?php
$teams = Array ( 
   21 => Array ( 
      'name' => Whitesox,
      'wins' => 8 ,
      'losses' => 5 ,
      'ties' => 1 
   ),
   20 => Array (
      'name' => Yankees ,
      'losses' => 10 ,
      'wins' => 3 ,
      'ties' => 1 
   ), 
   22 => Array (
      'name' => Cardinals ,
      'losses' => 12 ,
      'wins' => 2 
   ), 
   23 => Array (
      'name' => Reds ,
      'wins' => 11 ,
      'losses' => 1 ,
      'ties' => 1 
   ), 
   24 => Array (
      'name' => Rangers ,
      'wins' => 11 ,
      'ties' => 1 ,
      'losses' => 1 
   ), 
   25 => Array (
      'name' => Redsox ,
      'losses' => 9 ,
      'wins' => 3 ,
      'ties' => 2 
   )
);
function myCompare($x, $y)
{  // mult. wins by 2 rather than ties by .5 so that we do integer math
   $xTotal = ($x['wins'] * 2) + $x['ties'];
   $yTotal = ($y['wins'] * 2) + $y['ties'];
   return($yTotal - $xTotal);
} 
usort($teams, 'myCompare');
printf("<pre>%s</pre>", print_r($teams, 1));

Output:

Array
(
    [0] => Array
        (
            [name] => Rangers
            [wins] => 11
            [ties] => 1
            [losses] => 1
        )

[1] => Array
    (
        [name] => Reds
        [wins] => 11
        [losses] => 1
        [ties] => 1
    )

[2] => Array
    (
        [name] => Whitesox
        [wins] => 8
        [losses] => 5
        [ties] => 1
    )

[3] => Array
    (
        [name] => Redsox
        [losses] => 9
        [wins] => 3
        [ties] => 2
    )

[4] => Array
    (
        [name] => Yankees
        [losses] => 10
        [wins] => 3
        [ties] => 1
    )

[5] => Array
    (
        [name] => Cardinals
        [losses] => 12
        [wins] => 2
    )

)

[phattymatty]

That is the correct sorting.

[phattymatty]

How would I run the loop to do the same thing that my previous method did? I need to get wins, losses, ties, then calculate PCT, GB, Runs allowed (from function), Runs Scored (from fn) and Run Ratio (from fn) for each team in order of ranking.

I know I need some form of foreach loop. Won't the for each end though when it runs through the defined variables and go to the next line (ex: $team[0] to $team[1]) after the foreach executes? I still need to include a <tr> for the other data and keep it all in the loop.

Thanks so much for your help.

[phattymatty]

NogDog wrote:

Is this what you want?

<?php
$teams = Array ( 
   21 => Array ( 
      'name' => Whitesox,
      'wins' => 8 ,
      'losses' => 5 ,
      'ties' => 1 
   ),
   20 => Array (
      'name' => Yankees ,
      'losses' => 10 ,
      'wins' => 3 ,
      'ties' => 1 
   ), 
   22 => Array (
      'name' => Cardinals ,
      'losses' => 12 ,
      'wins' => 2 
   ), 
   23 => Array (
      'name' => Reds ,
      'wins' => 11 ,
      'losses' => 1 ,
      'ties' => 1 
   ), 
   24 => Array (
      'name' => Rangers ,
      'wins' => 11 ,
      'ties' => 1 ,
      'losses' => 1 
   ), 
   25 => Array (
      'name' => Redsox ,
      'losses' => 9 ,
      'wins' => 3 ,
      'ties' => 2 
   )
);
function myCompare($x, $y)
{  // mult. wins by 2 rather than ties by .5 so that we do integer math
   $xTotal = ($x['wins'] * 2) + $x['ties'];
   $yTotal = ($y['wins'] * 2) + $y['ties'];
   return($yTotal - $xTotal);
} 
usort($teams, 'myCompare');
printf("<pre>%s</pre>", print_r($teams, 1));

Output:

Array
(
    [0] => Array
        (
            [name] => Rangers
            [wins] => 11
            [ties] => 1
            [losses] => 1
        )

[1] => Array
    (
        [name] => Reds
        [wins] => 11
        [losses] => 1
        [ties] => 1
    )

[2] => Array
    (
        [name] => Whitesox
        [wins] => 8
        [losses] => 5
        [ties] => 1
    )

[3] => Array
    (
        [name] => Redsox
        [losses] => 9
        [wins] => 3
        [ties] => 2
    )

[4] => Array
    (
        [name] => Yankees
        [losses] => 10
        [wins] => 3
        [ties] => 1
    )

[5] => Array
    (
        [name] => Cardinals
        [losses] => 12
        [wins] => 2
    )

)

How would I run the loop to do the same thing that my previous method did? I need to get wins, losses, ties, then calculate PCT, GB, Runs allowed (from function), Runs Scored (from fn) and Run Ratio (from fn) for each team in order of ranking.

I know I need some form of foreach loop. Won't the for each end when it runs through the defined variables and go to the next line (ex: $team[0] to $team[1]) after the foreach executes? I still need to include a <tr> for the other data and keep it all in the loop.

I guess I don't understand how to do foreach for a multidimensional array, and how to supplement with other data (similar to mysql_fetch_assoc) . Can anyone help?

[phattymatty]

In the last two arrays, order should be name, wins, losses, ties ... not losses after name.

NogDog wrote:

Is this what you want?

<?php
$teams = Array ( 
   21 => Array ( 
      'name' => Whitesox,
      'wins' => 8 ,
      'losses' => 5 ,
      'ties' => 1 
   ),
   20 => Array (
      'name' => Yankees ,
      'losses' => 10 ,
      'wins' => 3 ,
      'ties' => 1 
   ), 
   22 => Array (
      'name' => Cardinals ,
      'losses' => 12 ,
      'wins' => 2 
   ), 
   23 => Array (
      'name' => Reds ,
      'wins' => 11 ,
      'losses' => 1 ,
      'ties' => 1 
   ), 
   24 => Array (
      'name' => Rangers ,
      'wins' => 11 ,
      'ties' => 1 ,
      'losses' => 1 
   ), 
   25 => Array (
      'name' => Redsox ,
      'losses' => 9 ,
      'wins' => 3 ,
      'ties' => 2 
   )
);
function myCompare($x, $y)
{  // mult. wins by 2 rather than ties by .5 so that we do integer math
   $xTotal = ($x['wins'] * 2) + $x['ties'];
   $yTotal = ($y['wins'] * 2) + $y['ties'];
   return($yTotal - $xTotal);
} 
usort($teams, 'myCompare');
printf("<pre>%s</pre>", print_r($teams, 1));

Output:

Array
(
    [0] => Array
        (
            [name] => Rangers
            [wins] => 11
            [ties] => 1
            [losses] => 1
        )

[1] => Array
    (
        [name] => Reds
        [wins] => 11
        [losses] => 1
        [ties] => 1
    )

[2] => Array
    (
        [name] => Whitesox
        [wins] => 8
        [losses] => 5
        [ties] => 1
    )

[3] => Array
    (
        [name] => Redsox
        [losses] => 9
        [wins] => 3
        [ties] => 2
    )

[4] => Array
    (
        [name] => Yankees
        [losses] => 10
        [wins] => 3
        [ties] => 1
    )

[5] => Array
    (
        [name] => Cardinals
        [losses] => 12
        [wins] => 2
    )

)

[NogDog]

phattymatty wrote:

In the last two arrays, order should be name, wins, losses, ties ... not losses after name.

That's the order they appeared in the sample data you provided in your initial post. The usort is not touching that dimension of the array, only sorting the first (numbered) dimension.

[phattymatty]

Thanks NogDog, I am a victim of overthinking this I am afraid!! Just out of curiosity, if I wanted to further sort my standings, in the event of two teams with even wins, losses, ties, lets say::: the next sort level would be runs allowed followed by runs scored. How would I do that? Would I have to include those statistics in my array for each team?

[Weedpacket]

The problem with using several usort() calls in a row is that subsequent sorts do not respect the order imposed by previous sorts. To use the technical term: the Quicksort algorithm (which usort() implements) is not stable.

What that means is that there is no guaranteed that any two elements that are equal (as far as the function usort() is using is concerned) will come out in the same order that they went in. For example, if you had

name       wins   losses
Redsox     3      9
Reds       8      1
Rangers    11     1
Whitesox   8      5

And you sorted by Wins, you could get either

name       wins   losses
Redsox     3      9
Whitesox   8      5
Reds       8      1
Rangers    11     1

or

name       wins   losses
Redsox     3      9
Reds       8      1
Whitesox   8      5
Rangers    11     1

(Because if you only look at wins, Reds and Whitesox are equal); and if you then sorted either of those by losses you'd get either

name       wins   losses
Reds       8      1
Rangers    11     1
Whitesox   8      5
Redsox     3      9

or

name       wins   losses
Rangers    11     1
Reds       8      1
Whitesox   8      5
Redsox     3      9

(because, looking only at losses, Rangers and Reds are equal).

There is no real way of predicting the output order of effectively equal elements - at least, not without doing so much analysis that you might as well be doing the sorting yourself - but in the tradeoff between performance and stability, performance wins.

The reason for that (and I'm finally getting to the solution) is because you can get all of the sorting done in one usort() call by doing all of the comparisons in a single function:

First, look at the most important field of the two elements (wins, in this case).
If they're different, you have your answer about which one should be before the other.
If they're the same, look at the next most important field (losses) and see if they differ. If they do you have your answer.
If the wins and losses were both the same, you break the tie by looking at the third field.

It's like sorting names: "Apthorp" comes before "Blofield" because 'A' comes before 'B', but "Aligheri" comes before "Arkwright" because 'l' comes before 'r'.

function compare_wins($x, $y)
{
	return $x['wins'] - $y['wins'];
}
function compare_losses($x, $y)
{
	return $x['losses'] - $y['losses'];
}
function compare_ties($x, $y)
{
	return $x['ties'] - $y['ties'];
}

function compare($x, $y)
{
	$wins = compare_wins($x, $y);
	if($wins) return $wins;
	$losses = compare_losses($x, $y);
	if($losses) return -$losses; // Descending
	$ties = compare_ties($x, $y);
	if($ties) return $ties;
	return 0;
}

(Incidentally, you have a bug in your comparelosses() test.)

[phattymatty]

function compare($x, $y)
{
$wins = compare_wins($x, $y);
if($wins) return $wins;
$losses = compare_losses($x, $y);
if($losses) return -$losses; // Descending
$ties = compare_ties($x, $y);
if($ties) return $ties;
return 0;
}

Thanks weedpacket. That helps shed alot of light on my sorting situation. I implemented the new usort and it works great. The only thing I had to change was the polarity of the returned vars in the COMPARE fn. The way you listed it actually listed the teams from last to first. This worked:

function compare($x, $y)
{
    $wins = compare_wins($x, $y);
    if($wins) return -$wins;
    $losses = compare_losses($x, $y);
    if($losses) return $losses; // Descending
    $ties = compare_ties($x, $y);
    if($ties) return -$ties;
    return 0;
}

Thanks a ton!

[Weedpacket]

Aye, or

function compare_wins($x, $y)
{
    return $y['wins'] - $x['wins'];
}