PHP即时在单个数字前加零开头，即时[重复]

<?php
$num = 4;
$num_padded = sprintf(\"%02d\", $num);
echo $num_padded; // returns 04
?>

%d

%s

sprintf(\"%04s\", 10);

sprintf(\"%04s\", -10);

sprintf(\"%04d\", 10);

sprintf(\"%04d\", -10);

str_pad($month, 2, \'0\', STR_PAD_LEFT); 

string str_pad ( string $input , int $pad_length [, string $pad_string = \" \" [, int $pad_type = STR_PAD_RIGHT ]] )

sprintf

$stamp = sprintf(\'%s%02s\', $year, $month);