How can the current day be highlighted without affecting the entire row in a PHP-generated table?

To highlight the current day in a PHP-generated table without affecting the entire row, you can use a conditional statement to add a specific class to the cell containing the current day. This class can then be styled using CSS to visually highlight the cell while leaving the rest of the row unchanged.

```php
<?php
// Get the current day
$currentDay = date('d');

// Iterate through the days and generate the table
echo '<table>';
for ($i = 1; $i <= 31; $i++) {
    echo '<tr>';
    for ($j = 1; $j <= 7; $j++) {
        if ($i == $currentDay) {
            echo '<td class="current-day">' . $i . '</td>';
        } else {
            echo '<td>' . $i . '</td>';
        }
        $i++;
    }
    echo '</tr>';
}
echo '</table>';
?>
```

In the above code snippet, we first get the current day using `date('d')`. Then, we iterate through the days to generate the table. If the current day matches the day being iterated, we add a class `current-day` to that cell. This class can then be styled using CSS to highlight the cell as needed.