$number = 1234567.89;
$formatted_number = number_format($number);
echo $formatted_number; // 输出：1,234,567.89
$number = 1234.56789;
$formatted_number = number_format($number, 2);
echo $formatted_number; // 输出：1,234.57
$number = 1234.56789;
$formatted_number = number_format($number, 2, ',', '.');
echo $formatted_number; // 输出：1.234,57
$number = -1234.56789;
$formatted_number = number_format($number, 2);
echo $formatted_number; // 输出：-1,234.57
$number = 1234567.89;
$formatted_number = number_format($number, 2, '.', '');
echo $formatted_number; // 输出：1234567.89
$number = 1.2e6;
$formatted_number = number_format($number, 0);
echo $formatted_number; // 输出：1,200,000
这些是一些常见的使用技巧，根据具体需求，可以灵活运用number_format函数来格式化数字。
