Comments on: Checking a string is alphanumeric in PHP

By: Avi

Avi — Wed, 01 Sep 2010 12:20:22 +0000

Hi
Thanks for this post.
ctype_alnum function works for me….

Thanks

By: Bijayani

Bijayani — Tue, 02 Feb 2010 13:18:48 +0000

Hi,

I happened to see your post find it quite informative. I would like to share a link where a software engineer has shared a tip on “Alphanumeric Random value in PHP”. I am sharing it just for the knowledge purpose.

Here is the link:
http://www.mindfiresolutions.com/PHP–Alphanumeric-Random-value-262.php

Hope you find it useful and of assistance.

Thanks,
Bijayani

By: Duncan

Duncan — Fri, 22 Jan 2010 16:00:28 +0000

Seems to be an error in your script

$alphanum2 = “Eagle,2008″;
print ctype_alnum($invalidUsername); // will return false

should it not be

$alphanum2 = “Eagle,2008″;
print ctype_alnum($alphanum2); // will return false

By: Shimon

Shimon — Tue, 11 Aug 2009 17:15:56 +0000

Thank you – I learned something new today!

By: webmaster

webmaster — Mon, 18 May 2009 02:29:51 +0000

hey Remo, sharp eyes thanks. I’ve fixed it.

By: Remo Laubacher

Remo Laubacher — Sat, 16 May 2009 08:19:09 +0000

You’re writing about “is_numeric”, but the code uses a non-existent function called “is_number”…

By: webmaster

webmaster — Mon, 09 Feb 2009 00:03:02 +0000

hi sadia
can you elaborate a bit more? are you saying your functions calls return errors?

By: sadia

sadia — Fri, 06 Feb 2009 11:23:43 +0000

do i hav to use some header file, as none of the function wrk for me

By: webmaster

webmaster — Mon, 21 Apr 2008 02:31:50 +0000

Thanks Fredrik.

You’re right, is_numeric actually does more than ctype_digit.

ctype_digit just checks for numbers making up a string and nothing more.

is_numeric will test for integer types as well as strings, and be able to determine negative numbers.

I’ve updated the post.

By: Fredrik Holmström

Fredrik Holmström — Fri, 18 Apr 2008 13:41:21 +0000

is_numeric and ctype_digit don’t do the same thing…