“Unknown modifier 'g' in…” when using preg_match in PHP?

问题:

This is the regex I'm trying to use:

/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/gim 

I found it on this site, and it works great when I try it out there. But as soon as I place it in my code, I get this message:

Warning: preg_match() [function.preg-match]: Unknown modifier 'g' in C:\xampp\htdocs\swebook\includes\classes.php on line 22 

Can anyone explain what's wrong, and why it's working on that website and not in my code?

回答1:

There is no modifier g for preg_match. Instead, you have to use the preg_match_all function.

So instead of:

preg_match("/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/gim", ....) 

use:

preg_match_all("/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/im", ....) 

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