当然不只是可以加0，去0，可以添加任何前导

添加前导：

使用PHP自己提供的函数：

str_pad

(PHP 4 >= 4.0.1, PHP 5)

str_pad -- Pad a string to a certain length with another string

Description

string str_pad ( string input, int pad_length [, string pad_string [, int pad_type]] )

This functions returns the input string padded on the left, the right, or both sides to the specified padding length. If the optional argument pad_string is not supplied, the input is padded with spaces, otherwise it is padded with characters from pad_string up to the limit.

Optional argument pad_type can be STR_PAD_RIGHT, STR_PAD_LEFT, or STR_PAD_BOTH. If pad_type is not specified it is assumed to be STR_PAD_RIGHT.

If the value of pad_length is negative or less than the length of the input string, no padding takes place.

例：

<?php
$input = "Alien";
echo str_pad($input, 10);                      // produces "Alien     "
echo str_pad($input, 10, "-=", STR_PAD_LEFT);  // produces "-=-=-Alien"
echo str_pad($input, 10, "_", STR_PAD_BOTH);   // produces "__Alien___"
echo str_pad($input, 6 , "___");               // produces "Alien_"
?>

去掉前导

使用正则

参考：

$pattern = “/(0+)(\d+)/i”;
$replacement = “\$2″;
$qid = preg_replace($pattern,$replacement,$qid);