Create Round Robin Using PHP
For those who have ever wanted to run a football league, or any sort of league requiring a round robin style of game draws, this simple function takes an array of team names (or numbers) and returns an array of the teams' games. This function also takes into account byes when an odd number of teams is given.
<?php
/**
*
* Create a round robin of teams or numbers
*
* @param array $teams
* @return $array
*
*/
function roundRobin( array $teams ){
if (count($teams)%2 != 0){
array_push($teams,"bye");
}
$away = array_splice($teams,(count($teams)/2));
$home = $teams;
for ($i=0; $i < count($home)+count($away)-1; $i++)
{
for ($j=0; $j<count($home); $j++)
{
$round[$i][$j]["Home"]=$home[$j];
$round[$i][$j]["Away"]=$away[$j];
}
if(count($home)+count($away)-1 > 2)
{
$s = array_splice( $home, 1, 1 );
$slice = array_shift( $s );
array_unshift($away,$slice );
array_push( $home, array_pop($away ) );
}
}
return $round;
}
?>
Usage
<?php
// create an array of teams
$members = array('team1','team2','team3','team4', 'team5', 'team6', 'team7', 'team8', 'team9');
// do the rounds
$rounds = roundRobin($members);
$table = "<table>\n";
foreach($rounds as $round => $games){
$table .= "<tr><th>Round: ".($round+1)."</th><th></th><th>Away</th></tr>\n";
foreach($games as $play){
$table .= "<tr><td>".$play["Home"]."</td><td>-v-</td><td>".$play["Away"]."</td></tr>\n";
}
}
$table .= "</table>\n";
echo $table;
?>
Demonstratrion
| Round: 1 | Away | |
|---|---|---|
| team1 | -v- | team6 |
| team2 | -v- | team7 |
| team3 | -v- | team8 |
| team4 | -v- | team9 |
| team5 | -v- | bye |
| Round: 2 | Away | |
| team1 | -v- | team2 |
| team3 | -v- | team6 |
| team4 | -v- | team7 |
| team5 | -v- | team8 |
| bye | -v- | team9 |
| Round: 3 | Away | |
| team1 | -v- | team3 |
| team4 | -v- | team2 |
| team5 | -v- | team6 |
| bye | -v- | team7 |
| team9 | -v- | team8 |
| Round: 4 | Away | |
| team1 | -v- | team4 |
| team5 | -v- | team3 |
| bye | -v- | team2 |
| team9 | -v- | team6 |
| team8 | -v- | team7 |
| Round: 5 | Away | |
| team1 | -v- | team5 |
| bye | -v- | team4 |
| team9 | -v- | team3 |
| team8 | -v- | team2 |
| team7 | -v- | team6 |
| Round: 6 | Away | |
| team1 | -v- | bye |
| team9 | -v- | team5 |
| team8 | -v- | team4 |
| team7 | -v- | team3 |
| team6 | -v- | team2 |
| Round: 7 | Away | |
| team1 | -v- | team9 |
| team8 | -v- | bye |
| team7 | -v- | team5 |
| team6 | -v- | team4 |
| team2 | -v- | team3 |
| Round: 8 | Away | |
| team1 | -v- | team8 |
| team7 | -v- | team9 |
| team6 | -v- | bye |
| team2 | -v- | team5 |
| team3 | -v- | team4 |
| Round: 9 | Away | |
| team1 | -v- | team7 |
| team6 | -v- | team8 |
| team2 | -v- | team9 |
| team3 | -v- | bye |
| team4 | -v- | team5 |