php递归,静态变量,匿名函数使用
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2022-04-13 15:02:11
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<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Current To-Do List</title>
</head>
<body>
<?php
function make_list($parent) {
global $tasks;
echo '<ol>';
foreach($parent as $task_id => $todo) {
echo "<li>$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 "</li>";
}
echo '</ol>';
}
$db = mysqli_connect('192.168.31.172' ,'root', 'root', 'phpadvanced');
mysqli_query($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] = $task;
}
//echo '<pre>'.print_r($tasks,1).'</pre>';
make_list($tasks[0]); //把包含*任务的数组发送给它, 最*的parent_id是0
?>
</body>
</html>
静态变量统计次数代码
<?php
// create the array.
// Array structs
// StudentId = > ["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 "<p>Iteration $count: {$x['name']} vs. {$y['name']} </p>\n";
$count ++;
return strcasecmp($x['name'], $y['name']);
}
function grade_sort($x, $y) {
static $count = 1;
echo "<p>Iteration $count: {$x['grade']} vs. {$y['grade']}</p>\n";
$count++;
return $x['grade'] < $y['grade'];
}
echo print_r($students, 1);
uasort($students, 'name_sort'); //保持键并使用自定义排序
echo print_r($students, 1);
uasort($students, 'grade_sort');
echo print_r($students, 1);
?>
匿名函数--闭包代码
<?php
// create the array.
// Array structs
// StudentId = > ["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'] < $y['grade'];
});
echo print_r($students, 1);
?>
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
<?php
function increment(&$i) {
$i++;
}
$num = 2;
increment($num);
echo $num;
?>
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