PHP recursion, static variables, anonymous function use-PHP Tutorial-php.cn

PHP recursion, static variables, anonymous function use

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Release： 2016-08-08 09:20:41

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<!doctype html>
<html lang="en">
<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] = $task;
}
//echo '<pre class="brush:php;toolbar:false">'.print_r($tasks,1).'

'; make_list($tasks[0]); //把包含顶级任务的数组发送给它, 最顶级的parent_id是0 ?>

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<?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);
?>

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<?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);
?>

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<?php
function increment(&$i) {
    $i++;
}
$num = 2;
increment($num);
echo $num;

?>

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The above introduces the use of PHP recursion, static variables, and anonymous functions, including aspects of it. I hope it will be helpful to friends who are interested in PHP tutorials.