php遞迴,靜態變數,匿名函數使用

遞迴讀取工作清單代碼

                Current To-Do List      ';            foreach($parent as $task_id => $todo) {              echo "
$todo";                if (isset($tasks[$task_id])) { // 如果當前id有子任務則遞迴建立菜單                  make_list($tasks[$task_id]);              }                echo "
";          }            echo '';      }        $db = mysqli_connect('192.168.31.172' ,'root', 'root', 'phpadvanced');      mysqli_query($db, "set names utf8");      $q = 'SELECT task_id, parent_id, task FROM tasks WHERE date_completed="0000-00-00 00:00:00" ORDER BY parent_id, date_added ASC';      $r = mysqli_query($db, $q);        $tasks = array();  while (list($task_id, $parent_id, $task) = mysqli_fetch_array($r, MYSQLI_NUM)) {      $tasks[$parent_id][$task_id] = $task;  }  //echo '
'.print_r($tasks,1).'
';  make_list($tasks[0]); //把包含頂級任務的數組發送給它, 最頂級的parent_id是0  ?>    

靜態變數統計次數代碼

 ["name" => "Name", "grade" => xx.x];    $students = [      256 => ['name' => 'Jon', 'grade' => '98.5'],      2 => ['name' => 'Vance', 'grade' => '85.1'],      9 => ['name' => 'Stephen', 'grade' => '94.0'],      364 => ['name' => 'Steve', 'grade' => '85.1'],      68 => ['name' => 'Rob', 'grade' => '74.6'],  ];    function name_sort($x, $y) {      static $count = 1;      echo "
Iteration $count: {$x['name']} vs. {$y['name']} 
\n";      $count ++;      return strcasecmp($x['name'], $y['name']);  }    function grade_sort($x, $y) {      static $count = 1;      echo "
Iteration $count: {$x['grade']} vs. {$y['grade']}
\n";      $count++;      return $x['grade'] < $y['grade'];  }    echo print_r($students, 1);  uasort($students, 'name_sort'); //保持鍵並使用自訂排序  echo print_r($students, 1);  uasort($students, 'grade_sort');  echo print_r($students, 1);  ?>

匿名函數--閉包代碼

 ["name" => "Name", "grade" => xx.x];    $students = [      256 => ['name' => 'Jon', 'grade' => '98.5'],      2 => ['name' => 'Vance', 'grade' => '85.1'],      9 => ['name' => 'Stephen', 'grade' => '94.0'],      364 => ['name' => 'Steve', 'grade' => '85.1'],      68 => ['name' => 'Rob', 'grade' => '74.6'],  ];    echo print_r($students, 1);  uasort($students, function($x, $y){      return strcasecmp($x['name'], $y['name']);  }); //保持鍵並使用自訂排序  echo print_r($students, 1);  uasort($students, function($x, $y){      return $x['grade'] < $y['grade'];  });  echo print_r($students, 1);  ?>

引用傳參, 當資料是一個大資料的時候使用, 就不需要拷貝資料的副本了代碼

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