Regular expression with a * in php

I want to use a basic regular exp开发者_高级运维ression to check whether a string contains only numbers and alphabet characters so I tried

preg_match('[a-zA-Z0-9]*', $address)

Which unfortunately returns an error:

Warning: preg_match() [function.preg-match]: Unknown modifier '*' in /bla/bla.php on line XX

It's a simple regex. Where am I getting it wrong?

The pattern should begin and end with a pattern delimiter. Different preg options, like case-insensitive search can be added after the delimiter. Usually slash (/) is used for delimiter, but can be any symbol (the delimiter should be escaped in the pattern):

preg_match('/[a-z0-9]*/i', $address);

This will check if the string has numbers or characters in it.

If you want to make sure that it has only numbers and characters, then use this:

preg_match('/^[a-z0-9]*$/i', $address);

You can use ctype_alnum instead.

I use this to find all possible alphabetic characters from different languages as well:

preg_match('/^[\p{L}\p{M}0-9]+$/i', $address);

But if just English then:

preg_match('/^[a-z0-9]+$/i', $address);

use

preg_match('/^[a-zA-Z0-9]*$/', $address)

you forgot the slashes for the regex :

preg_match('/[a-zA-Z0-9]*/', $address)

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