[SOLVED] only numbers

[dadamssg]

im using a variable passed the url as in mysite.com/work.php?id=45. I $_GET that number and use it in query in my database. I just need a simple pattern that checks whether its numerical or not. I don't want someone typing in sql in the url, refreshing and then a table is dropped or something. If the url is not a number, ill send them to the homepage or something. thanks, any advice would be awesome!

[corbin]

http://php.net/ctype_digit

 

(Note that with PHP < 5.1 it accepted empty strings as numeric.)

 

 

But, if you really want to go the regexp route (which there is no need for):

 

if(preg_match('~[\d]+~', $something)) {

    //$something consists of 1 or more digits

}

[nrg_alpha]

corbin, I definitely agree with you on using ctype_digit on this one. Note however that your pattern (should the OP go this route [and again, I personally wouldn't, not for stuff like this]) doesn't need the character class square brackets, as \d is already a short-hand character class for digits in its own right.

 

[dadamssg]

perfect, thanks!

[corbin]

Hrmmm, guess I've been having a slow moment for a long time.  I thought shorthand character classes were only valid in [].

 

I learn new things every day ;p.

[nrg_alpha]

I thought shorthand character classes were only valid in [].

 

No, stuff like \d, \w etc... function just the same whether they are inside or outside a character class. Since \d matches exponents as well, and say you wanted only 0-9, then you would need to encase 0-9 within a character class, as 0-9 alone is not a short-hand character class of any sort.

~[0-9]+~

 

The only time (that I can think of at the moment) where you would need to wrap character class brackets around those is if:

a) you want to check for additional stuff, like a string consisting of only \d or - characters:

 

~[\d-]+~ // I'm ignoring ^, $, \A and \z stuff for 'expression simplicity' sake.

 

b) you want to match / capture anything that is not listed (thus using a negated character class):

~[^\d]+~

[corbin]

Wow I just realized that my regexp earlier, not only was it bad, but it was entirely wrong ;p.  It would have needed ^ and $.

 

 

Hrmmm I had always thought \d was 0-9.  Guess it makes sense that it's other stuff too though.

 

 

I swear I'm not regular expressionally retarded....  Just slow ;p.

[nrg_alpha]

Hrmmm I had always thought \d was 0-9

 

Yeah, this is the common belief. Granted, in most cases, \d will in fact do just fine.. (as how often does one actually run into exponents?). But it's a nice thing to know in the event exponents do find their way into strings.

 

 

I swear I'm not regular expressionally retarded....  Just slow ;p.

 

lol, I know you not. Not even slow..we all have our 'off days', and god knows, I've had more than my fair share (with more to come I'm sure!).

[corbin]

Hrmmmm wonder how the OP's query would've responded to something like 10^5 lol.