Control inputs

[Anon]

Hi:
I have to control what kind of data I receive, making differences between strings of caracthers and numbers.
How can I control if that data that I receive is a number or a caracter.?
Please, I need help with this.

What are the functions in php to determine the data that I receive?

Thanks.

Luis
[e-mail]

[spacemax]

ereg("abc",$string);
/ Returns true if "abc"
is found anywhere in $string. /
ereg("^{abc",$string);}
/ Returns true if "abc"
is found at the beginning of $string. /
ereg("abc$",$string);
/ Returns true if "abc"
is found at the end of $string. /
eregi("(ozilla.[23]|MSIE.3)",$HTTP_USER_AGENT);
/ Returns true if client browser
is Netscape 2, 3 or MSIE 3. /
ereg("([[:alnum:]]+) ([[:alnum:]]+) ([[:alnum:]]+)",
$string,$regs);
/ Places three space separated words
into $regs[1], $regs[2] and $regs[3]. /