PHP数字前补0的自带函数_PHP教程

<?php   
	//生成4位数，不足前面补0   
    $var=sprintf("%04d", 2);
    echo $var;//结果为0002   
	
	echo date('Y_m_d', time()).'_'.sprintf('d', rand(0,99));
?> 

sprintf(format,arg1,arg2,arg++)

<?php   
$number = 123;   
$txt = sprintf("%f",$number);   
echo $txt;   
?> 

<?php   
$number = 1234.56;

// english notation (default)
$english_format_number = number_format($number);
// 1,235

// French notation
$nombre_format_francais = number_format($number, 2, ',', ' ');
// 1 234,56

$number = 1234.5678;

// english notation without thousands seperator
$english_format_number = number_format($number, 2, '.', '');
// 1234.57
?>