在 PHP 中使用条件语句进行二维关联数组排序

Posted 2023-02-23

【中文标题】在 PHP 中使用条件语句进行二维关联数组排序

【英文标题】：2 dimensional associative array sorting with conditional statements in PHP

【发布时间】：2019-03-05 09:51:26

【问题描述】：

我无法弄清楚如何解决这个问题，它来自一个免费的在线测试网站。这是链接：https://www.testdome.com/questions/php/league-table/19939?questionIds=7278,19939&generatorId=30&type=fromtest&testDifficulty=Hard

但为了更清楚，我也在写这个问题和我的答案。开始的答案在上面写的链接中。

问题：

LeagueTable 类跟踪联盟中每个玩家的得分。每场比赛结束后，玩家使用 recordResult 函数记录他们的得分。

玩家在联赛中的排名使用以下逻辑计算：

得分最高的玩家排名第一（排名 1）。得分最低的玩家排名最后。 如果两名球员得分相同，则比赛次数最少的球员排名较高。 如果两名球员的得分和比赛次数并列，那么在球员名单中排名第一的球员排名更高。 实现 playerRank 函数，返回给定排名的玩家。

例如：

$table = new LeagueTable(array('Mike', 'Chris', 'Arnold'));
$table->recordResult('Mike', 2);
$table->recordResult('Mike', 3);
$table->recordResult('Arnold', 5);
$table->recordResult('Chris', 5);
echo $table->playerRank(1);

所有玩家的得分相同。不过，阿诺德和克里斯的比赛场次都比迈克少，而且由于克里斯在球员名单中排在阿诺德之前，所以他排名第一。因此，上面的代码应该显示“Chris”。

我的代码：

<?php

class LeagueTable

    public function __construct($players)
    
        $this->standings = array();
        foreach($players as $index => $p)
        
            $this->standings[$p] = array
            (
                'index' => $index,
                'games_played' => 0, 
                'score' => 0
            );
        
    

    public function recordResult($player, $score)
    
        $this->standings[$player]['games_played']++;
        $this->standings[$player]['score'] += $score;
    

    public function playerRank($rank)
    
        // I'm not sure what to do in here, not even sure where to place the conditional statements
        // but here's me trying to figure it out which I'm 90% sure I'm doing it wrong, 
        // since I'm using too many foreach function and arrays. Most probably not even close
        // to the correct answer.

        $comparison = $result = $this->standings;
        $player_names = array();

        foreach($this->standings as $name => $records)
        
            foreach($comparison as $name_compare => $records_compare)
                 
                if($this->standings[$name]['score'] > $comparison[$name_compare]['score'])
                
                    $result[$name]['index'] = $this->standings[$name]['index'];
                
                else if($this->standings[$name]['score'] == $comparison[$name_compare]['score']
                      && $this->standings[$name]['games_played'] < $comparison[$name_compare]['games_played'])
                
                    $result[$name]['index'] = $this->standings[$name]['index'];
                
                else if($this->standings[$name]['score'] == $comparison[$name_compare]['score']
                        && $this->standings[$name]['games_played'] == $comparison[$name_compare]['games_played'])
                
                    $result[$name]['index'] = $this->standings[$name]['index'];
                

                // This is where I'm confused, although there are conditional statemens there
                // but the code inside each "if" and "else if" is the same.

            
        

        foreach($result as $name => $records)
        
            array_push($player_names,$name);
        

        return $player_names[$rank-1]; //This should return "Chris" based on the record result, but it's not
    


$table = new LeagueTable(array('Mike', 'Chris', 'Arnold'));
$table->recordResult('Mike', 2);
$table->recordResult('Mike', 6);
$table->recordResult('Arnold', 5);
$table->recordResult('Chris', 5);
echo $table->playerRank(1);

谁能帮我解决这个问题？

【问题讨论】：

按usort函数排序数组 - php.net/manual/en/function.usort.php

谢谢，但我仍然不知道如何应用usort 函数来回答这个问题。如果您能在答案部分告诉我您的方式，我将不胜感激，以便我更好地理解并了解有关数组排序的更多信息

【参考方案1】：

在你的情况下使用 usort

usort($this->standings, function($a, $b) 
  // Compare scores
  $r = $b['score'] - $a['score'];
  // If two players are tied on score, 
  // then the player who has played the fewest games is ranked higher
  if(! $r) 
    $r = $a['games_played'] - $b['games_played'];
  
  // If two players are tied on score and number of games played, 
  // then the player who was first in the list of players is ranked higher
  if(! $r) 
    $r = $a['index'] - $b['index'];
  
  return $r;        
);

// You can watch result of sorting
print_r($this->standings);

【参考方案2】：

您可以在下面找到完整的答案

<?php
class LeagueTable

    public function __construct($players)
    
        $this->standings = array();
        foreach($players as $index => $p)
        
            $this->standings[$p] = array
            (
                'index' => $index,
                'games_played' => 0, 
                'score' => 0,
                'rank' => $index
            );
        
    

    public function recordResult($player, $score)
    
        $this->standings[$player]['games_played']++;
        $this->standings[$player]['score'] += $score;
    

    function swap(&$x,&$y) 
        $tmp=$x;
        $x=$y;
        $y=$tmp;
      

    public function reRank()
    
       //ranking all according to score
        foreach($this->standings as $player => $records) 

          foreach($this->standings as $player1 => $records1) 

            if (($records['score'] > $records1['score']) && ($records['rank'] >= $records1['rank']))
            
                $this->swap($this->standings[$player]['rank'],$this->standings[$player1]['rank']);
            

            // according to game played
            if (($records['score'] == $records1['score']) && ($records['games_played'] > $records1['games_played']))
            
                $this->swap($this->standings[$player]['rank'],$this->standings[$player1]['rank']);
            

            // according to index
            if (($records['score'] == $records1['score']) && ($records['games_played'] == $records1['games_played'])&&
            ($records['index'] > $records1['index']))
            
                $this->swap($this->standings[$player]['rank'],$this->standings[$player1]['rank']);
            
          
       
    

    public function playerRank($rank)
    
        $this->reRank();
        foreach($this->standings as $player => $records)
        
            if ($records['rank']==$rank-1)
            return $player;
        
    


$table = new LeagueTable(array('Chris', 'Mike', 'Arnold'));
$table->recordResult('Mike', 2);
$table->recordResult('Mike', 3);
$table->recordResult('Arnold', 5);
$table->recordResult('Chris', 5);

echo $table->playerRank(1);
?>

【讨论】：

这似乎无法正确排序项目。返回的第一个项目名称应为 Chris，但此函数生成“Mike”。

【参考方案3】：

请尝试以下代码。它会起作用的。

<?php
class LeagueTable

    public function __construct($players)
    
        $this->standings = array();
        foreach($players as $index => $p)
        
            $this->standings[$p] = array
            (
                'index' => $index,
                'games_played' => 0, 
                'score' => 0,
                'name' => $p
            );
        
    

    public function recordResult($player, $score)
    
        $this->standings[$player]['games_played']++;
        $this->standings[$player]['score'] += $score;
    

    public function playerRank($rank)
    

        $comparison = $result = $this->standings;
        $player_names = array();
       
       usort($this->standings, "comparatorFunc");
       

        foreach($this->standings as $name => $records)
        
            array_push($player_names,$records['name']);
        
        // echo "hello<br>";
        // print_r($player_names);
        return $player_names[$rank-1]; 
    



function comparatorFunc($a, $b) 
    # Compare scores
    $r = $b['score'] - $a['score'];
    # If two players are tied on score, 
    # then the player who has played the fewest games is ranked higher
    if(! $r) 
        $r = $a['games_played'] - $b['games_played'];
    
    # If two players are tied on score and number of games played, 
    # then the player who was first in the list of players is ranked higher
    if(! $r) 
        $r = $a['index'] - $b['index'];
    
    return $r;        

    
$table = new LeagueTable(array('Mike', 'Chris', 'Arnold'));
$table->recordResult('Mike', 2);
$table->recordResult('Mike', 6);
$table->recordResult('Arnold', 2);
$table->recordResult('Arnold', 3);
$table->recordResult('Chris', 5);
echo $table->playerRank(1);

【讨论】：

您的答案可以通过额外的支持信息得到改进。请edit 添加更多详细信息，例如引用或文档，以便其他人可以确认您的答案是正确的。你可以找到更多关于如何写好答案的信息in the help center。

【参考方案4】：

<?php
class LeagueTable

  public function __construct(array $players)
  
     $this->standings = [];
     foreach ($players as $index => $p) 
        $this->standings[$p] = [
            'index'        => $index,
            'games_played' => 0,
            'score'        => 0
        ];
      
   

    public function recordResult(string $player, int $score): void
    
       $this->standings[$player]['games_played']++;
       $this->standings[$player]['score'] += $score;
    

    public function playerRank(int $rank): string
    
       $result = '';
      /**
       * sort array
       */
       uasort($this->standings, function ($player, $other_player) 
            $r = $other_player['score'] - $player['score'];
            if (!$r) 
                 $r = $player['games_played'] - 
                         $other_player['games_played'];
            
            if (!$r) 
                $r = $player['index'] - $other_player['index'];
            
           return $r;
         );
         if ($rank > count($this->standings)) 
              $rank = count($this->standings);
         
         $index = 1;
         foreach ($this->standings as $player => $player_result) 
           if ($index == $rank) 
               $result = $player;
               break;
             else 
               $index++;
               continue;
           
         
        return $result;
       
 

      $table = new LeagueTable(array('Mike', 'Chris', 'Arnold', 'Ali', 
                              'Ahmad'));
     $table->recordResult('Mike', 2);
     $table->recordResult('Mike', 3);
     $table->recordResult('Arnold', 5);
     $table->recordResult('Chris', 5);
     $table->recordResult('Ali', 6);
     $table->recordResult('Ahmad', 3);
     $table->recordResult('Ahmad', 3);
     echo $table->playerRank(1);

【讨论】：

您好，如果您能帮助我们了解您的代码的作用以及它如何解决 OP 的问题，那就太好了！