How to replace eregi()

问题

I tried looking around and thought i figured it out by using preg_match, but preg match gives me the error:

Warning: preg_match(): No ending delimiter '^'

here is my original code which php says is depreciated:

if(!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $_POST['email'])) { 
    $erroR= "Invalid Email address"; 
} 

can someone explain what the ending delimiter '^' is, and how to add it. thanks@

回答1:

Swap eregi() with preg_match(), and add delimiters to the regular expression. I chose the standard / here, but you can use other characters.

if(!preg_match("/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/", $_POST['email'])) { 
    $erroR= "Invalid Email address"; 
} 

The reason you get this warning...

Warning: preg_match(): No ending delimiter '^'

...is because preg_match() expects delimiters, and it assumed the ^ was being used, and it couldn't match a trailing one.

回答2:

Add a / before and after your expression - you need a delimiter for preg_replace to tell it where the regex starts and finishes. It can be:

A delimiter can be any non-alphanumeric, non-backslash, non-whitespace character.
Often used delimiters are forward slashes (/), hash signs (#) and tildes (~).

So this will work:

"/^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$/"

来源：https://stackoverflow.com/questions/9204704/how-to-replace-eregi