PHP foreach 数组输出到带有空单元格的表

Question

我正在尝试为自己制定一个简单的教学计划，但卡在了我的数组的输出上。

这是 PHP：

echo '<table><thead><tr><th>Period</th><th>1</th><th>2</th><th>3</th>th>4</th><th>5</th><th>6</th><th>7</th><th>8</th><th>9</th></tr>';
echo '<tr><th>Time</th><th>08:50</th><th>09:40</th><th>10:30</th><th>11:20</th><th>12:10</th><th>13:00</th><th>13:50</th><th>14:40</th><th>13:30</th></tr>';
echo '</thead><tbody>';
$results = $db->mysql->query("SELECT * FROM schedule");
if ($results->num_rows) {
    while ($row = $results->fetch_assoc()) {
        $days[$row['day']][$row['period']] = $row['classroom'];
    } // close days while

    foreach ($days as $key => $val) {
        echo '<tr><td>' . $key .
            '</td>';
        foreach ($val as $item) {
            echo '<td>' . $item .
                '</td>';
        }
        echo '</tr>';
    }
}
echo '</tbody></table>';

这给了我一个这样的数组：

Array
(
[Monday] => Array
    (
        [1] => m5 biology
        [6] => m5 ict
        [8] => m6 ict
    )

[Tuesday] => Array
    (
        [3] => m5 biology
        [6] => m6 ict
        [7] => m6 ict
    )

[Wednesday] => Array
    (
        [1] => m6 biology
        [2] => m5 ict
        [7] => m5 biology
        [8] => m2 ict
    )

[Thursday] => Array
    (
        [1] => m6 biology
    )

[Friday] => Array
    (
        [1] => m6 biology
        [6] => m6 ict
    )

表格输出如下所示：

...
<tr>
  <td>Monday</td>
  <td>m5 biology</td>
  <td>m5 ict</td>
  <td>m6 ict</td>
</tr>
...

我希望输出包含空闲时段的空表格单元格。在星期一的示例中，只有周期 1、6、8 的数据，因此它只显示这些单元格。

如何让此代码也输出 2、3、4、5、7、9 周期的空单元格？像这样：

...
<tr>
  <td>Monday</td>
  <td>m5 biology</td>
  <td>&nbsp</td>
  <td>&nbsp</td>
  <td>&nbsp</td>
  <td>&nbsp</td>
  <td>m5 ict</td>
  <td>&nbsp</td>
  <td>m6 ict</td>
  <td>&nbsp</td>
</tr>

我想过在 foreach 中使用 if 语句，但我不知道我需要建立什么样的关系。

任何帮助将不胜感激。

Answer 1

由于您使用的是数字键，并且您知道一周只有 7 天，因此不要使用 foreach()，而是使用 for()：

for($i = 1; $i <= 7; $i++) {
    if(isset($array[$i])) { 
       ... there's info for this day, output it
    } else {
       ... no info, output a blank cell
    }
}

Answer 2

试试这个

<?php
$data = array (
  "Monday" => Array
    (
        1 => "m5 biology",
        6 => "m5 ict",
        8 => "m6 ict",
    ),

  "Tuesday" => Array
    (
        3 => "m5 biology",
        6 => "m6 ict",
        7 => "m6 ict",
    ),

  "Wednesday" => Array
    (
        1 => "m6 biology",
        2 => "m5 ict",
        7 => "m5 biology",
        8 => "m2 ict",
    ),

  "Thursday" => Array
    (
        1 => "m6 biology",
    ),

  "Friday" => Array
    (
        1 => "m6 biology",
        6 => "m6 ict",
    )
);


$table = "<table border = '1'><tr><td>Day</td>";
for ($x = 1; $x<8; $x++) {
    $table .= "<td>Period $x</td>";
}   
$table .= "</tr>";
foreach ($data as $day => $classes) {
    $table .= "<tr><td>$day</td>";
    for ($x = 1; $x<8; $x++) {
        if (isset($classes[$x])) {
            $table .= "<td>" . $classes[$x] . "</td>";
        } else {
            $table .= "<td></td>";
        }
    }
    $table .= "</tr>";
}
$table .= "</table>";
echo $table;