if判断条件,session方法等

if条件判断中，0,NULL,''都是false

session方法

session('_userID', $userInfo['userID']);

//切换数据库

$infoClass = M()->db(1,C('DB_CONFIG_SYN'))->table('syn_userinfo');

//字符串替换
<?php
echo strtr("Hilla Warld","ia","eo");
?>

输出：Hello World 

//编码转换
$content = iconv("utf-8","gb2312//IGNORE",$content);