php递归,静态变量,匿名函数使用

递归读取任务列表代码

  
  
';  
  
        foreach($parent as $task_id => $todo) {  
            echo "

$todo"; if (isset($tasks[$task_id])) { // 如果当前id有子任务则递归创建菜单 make_list($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*任务的数组发送给它, 最*的parent_id是0 ?>

静态变量统计次数代码

 ["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'] 

匿名函数--闭包代码

 ["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'], $y['name']);  
}); //保持键并使用自定义排序  
echo print_r($students, 1);  
uasort($students, function($x, $y){  
    return $x['grade'] 

引用传参, 当数据是一个大数据的时候使用, 就不需要拷贝数据的副本了代码