[SOLVED] Allowing alphabetic and numbers only

[9three]

Hey

 

I have this pattern:

 

^([a-zA-Z])|(0-9) ([a-zA-Z])|(0-9)$

 

What I'm trying to accomplish:

 

1. Start with AND end with a alphabetic or number

2. Allow only alphabetic and numbers in the entire string.

 

Did I do it right?

 

Thanks

[Daniel0]

If it starts with and ends with either an alphanumeric character, and the string is only allowed to be comprised of alphanumeric characters, isn't that just ^[a-zA-Z0-9]+$ (or ctype_alnum)? Or am I missing something?

[9three]

ctype_alnum() would work. But isn't that function for either or? Not both? At least that's what I understand from the documentation.

[Daniel0]

ctype_alnum() checks if a string solely consists of alphanumeric characters. That is the alphabetic characters a-z and A-Z and the numeric characters 0-9. It's essentially the same as the regex I posted.

[nrg_alpha]

Theone caveat involving the use of functions like ctype_alnum() is your locale.

I explain it in this thread (reply #3).

[9three]

Great. thank you.

[9three]

When I use the pattern you provided it gives me an error

 

if (!preg_match('^[a-zA-Z0-9]+$', $strUsername))

 

^[a-zA-Z0-9]+$
Warning: preg_match() [function.preg-match]: No ending delimiter '^' found

 

I tried somethings like adding a / at the end but it was no good.

 

[nrg_alpha]

This is because in preg, you need to encase the entire pattern in delimiters... so in your case, you can use:

 

if (!preg_match('#^[a-z0-9]+$#i', $strUsername)) // note the opening and closing #.. I also used the i modifier for case insensitivity

 

Delimiters can be any non alphanumeric, non whitespace ASCII character (except a backslash). You can read up about delimiters here:

 

http://www.phpfreaks.com/forums/index.php/topic,95777.0.html

As well as the pcre portion of the manual.

[9three]

thanks friend!