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printf和sprintf的应用

巴扎黑
巴扎黑asal
2016-11-10 13:51:041404semak imbas


<?php  
printf(&#39;b: %b <br>c: %c <br>d: %d <bf>f: %f&#39;, 80,80, 80, 80);  
echo &#39;<br />&#39;;  
printf(&#39;%0.2f <br>%+d <br>%0.2f <br>&#39;, 8, 8, 1235.456);  
  
printf(&#39;the cost of %d %s at $%0.2f each is $%0.2f.&#39;, 4, &#39;brooms&#39;, 8.50, (4*8.50));  
  
echo &#39;<br>&#39;;  
$tax = 30;  
printf(&#39;The tax rate is %0.2f%%&#39;, $tax);

Sprint可以把查询和数据很好的分开代码  

<!doctype html>  
<html lang="en">  
<head>  
    <meta charset="utf-8">  
    <title>Sorting Multidimensional Arrays</title>  
</head>  
<body>  
<?php  
$db = mysqli_connect(&#39;192.168.31.172&#39;, &#39;root&#39;, &#39;root&#39;, &#39;phpadvanced&#39;);  
mysqli_query($db, "set names utf8");  
  
if(!empty($_POST[&#39;task&#39;])) {  
    $parent_id = 0;  
    if(isset($_POST[&#39;parent_id&#39;]) && filter_var($_POST[&#39;parent_id&#39;], FILTER_VALIDATE_INT, [&#39;min_range&#39; => 1])) {  
        $parent_id = $_POST[&#39;parent_id&#39;];  
    }  
  
    $q = sprintf("INSERT INTO tasks (parent_id, task) VALUES (%d, &#39;%s&#39;)", $parent_id, mysqli_real_escape_string($db, strip_tags($_POST[&#39;task&#39;])));  
    $r = mysqli_query($db, $q);  
  
    if(mysqli_affected_rows($db) == 1) {  
        echo &#39;<p>任务添加成功</p>&#39;;  
    } else {  
        echo &#39;<p>任务添加失败</p>&#39;;  
    }  
}  
?>  
    <form action="add_task.php" method="post">  
        <fieldset>  
            <legend>添加一个任务</legend>  
            <p>任务: <input name="task" type="text" size="60" maxlength="100" required> </p>  
            <p>上级任务: <select name="parent_id">  
                    <option value="0">无上级</option>  
  
                    <?php  
                    $q = &#39;SELECT task_id, parent_id, task FROM tasks WHERE date_completed="0000-00-00 00:00:00" ORDER BY date_added ASC&#39;;  
                    $r = mysqli_query($db, $q);  
                    $tasks = [];  
                    while(list($task_id, $parent_id, $task) = mysqli_fetch_array($r, MYSQLI_NUM)) {  
                        echo "<option value=\"$task_id\">$task</option>";  
                        $tasks[] = [&#39;task_id&#39; => $task_id, &#39;parent_id&#39; => $parent_id, &#39;task&#39; => $task];  
                    }  
                    ?>  
                </select></p>  
            <input name="submit" type="submit" value="添加这个任务" />  
        </fieldset>  
    </form>  
  
<?php  
    // 对任务的父id进行排序  
    function parent_sort($x, $y) {  
        return ($x[&#39;parent_id&#39;] > $y[&#39;parent_id&#39;]);  
    }  
    usort($tasks, &#39;parent_sort&#39;);  
    echo &#39;<h2>当前的任务列表</h2><ul>&#39;;  
    foreach ($tasks as $task) {  
        echo "<li>{$task[&#39;task&#39;]}</li>\n";  
    }  
echo &#39;</ul>&#39;;  
?>  
</body>  
</html>


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