Get all possible combinations of a PHP Array split in two - php

Question

Im working on a code for generating a sports teams. I have an array with a list of players and want to store on another array all the possible team cobinations.
To make it simple, lets imagine a tennis match, where you have 4 players that will be split into two teams.
$players = array("Federer","Del Potro","Nadal","Murray");
The output array should look something like this:
$combinations[0][0] = "Federer","Del Potro";
$combinations[0][1] = "Nadal","Murray";
$combinations[1][0] = "Federer","Nadal";
$combinations[1][1] = "Del Potro","Murray";
$combinations[2][0] = "Del Potro","Nadal";
$combinations[2][1] = "Federer","Murray"; .. and so forth..
Any help?
Thanks in advance!
/// -- Edit
This is the code I have so far. All players also have a score and I store this score for later usage. Its not really important. I think I've got it working but im not sure this code gets ALL the possible combinations. What I do is I loop "player count" times and start building teams, after a team is built , I move the second player of the list to the bottom of the array and loop again.
//-- Get the Max Players and the Array of Player Names
$max_players = count($players)/2;
$p = array_keys($players);
for($i=0;$i<=(count($p));$i++){
$tmp = array();
$t=0;
//-- Loop and start placing players into a team. When the max is reached, start placing on the other team.
foreach($p as $player) {
//-- Store player on Team
$tmp[$t][] = $player;
if(count($tmp[$t])==$max_players) {
$t++;
}
}
//-- Get the second player and move it to the bottom of the list.
$second = $p[1];
unset($p[1]);
$p[] = $second;
$p = array_values($p);
//-- Loop thru teams and add the score of each player
foreach($tmp as $key=>$eq) {
$score = 0 ;
foreach($eq as $jug) {
//-- Add Score for each player
$score += floatval($players[$jug]["score"]);
}
//-- Store the sum of scores of all players in team
$tmp[$key]["score"] = $score;
}
//-- Store the Difference between team scores in this "team set"
$tmp["diff"] = abs(round($tmp[0]["score"]-$tmp[1]["score"],2));
$teams[] = $tmp;
}

Answer 1

Just googled and found these results from stackoverflow.com
Get all combinations of a PHP array
algorithm that will take numbers or words and find all possible combinations
PHP: How to get all possible combinations of 1D array?

Answer 2

$player_combination = [];
$match_combination = [];
$players = array("Federer","Del Potro","Nadal","Murray");
for($i = 0; $i< count($players);$i++){
for($j=$i+1;$j<count($players);$j++){
$player_combination[] = [$players[$i],$players[$j]];
}
}
for($i = 0; $i< count($player_combination);$i++){
for($j=$i+1;$j<count($player_combination);$j++){
if(($player_combination[$i][0] !== $player_combination[$j][0]) && ($player_combination[$i][0] !== $player_combination[$j][1])&& ($player_combination[$i][1] !== $player_combination[$j][0]) && ($player_combination[$i][1] !== $player_combination[$j][1]))
$match_combination[] = [$player_combination[$i],$player_combination[$j]];
}
}
my webiste is 9amobile.com