using eregi to validate integers

[bysonary]

hello, I am looking into validating a form field to see if it is an integer value or not, I am sure I need to use eregi but am not sure if what I am thinking will work, can someone offer me some advice.. I have the following idea..

$nextq = (int)$_POST['nextquest'];

if (eregi([0-9], $nextq))
{
//INSERT $nextq INTO THE DATABASE
}
else
{
//DISPLAY ERROR IDENTIFYING $nextq AS A NON INT
}

can someone tell me if my if statement looks right and perhaps if i could do it like this..

if (!eregi([0-9], $nextq))

sort of like if nextq is not an int

any help here would be appreciated

[Psychopsia]

Another way is:

if (preg_match('/^\d$/', $nextq))
{
// SQL
}

[bysonary]

ah cool so my way looks ok then does it even the if (!eregi()){} way?

[Psychopsia]

I think so, don't know exactly because I never use ereg o eregi.

if (!preg_match('/^\d$/', $nextq))
{
// ERROR
}

[bysonary]

Can you explain this I dont understand how this is checking to see if the value of the $nextq variable is an integer or not?

[Psychopsia]

Check this out: [webmasterworld.com...]

Specially on "Some special character sequences" block.

[edited by: Psychopsia at 6:04 pm (utc) on Feb. 12, 2007]

[dreamcatcher]

PHP has built in functions for checking for digits. Check out the ctype_digit [uk.php.net] function or you can use the character class [:digit:]

$string = '5';

if (ctype_digit($string))
{
//ok
}

if (ereg("^[[:digit:]]+$", $string))
{
//ok
}

dc

[bysonary]

when using

if (preg_match('/^\d$/', $nextq) && preg_match('/^\d$/', $weight))
{
// SQL
}
else
{
//ERROR
}

it doesnt work if enter the number 10 in any of the fields e.g.

$nextq = 7
$weight = 10

i get an error with the above if statement and the values, I tried

if (ctype_digit($nextq) && ctype_digit($weight))
{
//SQL
}
else
{
//ERROR
}

that ctype_digit code failed too, can anyone tell me how i can this to work when an integer of say "10" is entered?

[bysonary]

got it working finally with

if(is_numeric($nextq) && is_numeric($weight))

[bysonary]

is_numeric wasnt working properly it accepted a1 and b2 as valid when they contain alphabetic characters

I found out that ctype_digit works however the reason it wasnt working before was because i was testing $nextq

and $nextq = (int)$POST['next_qid'];

the (int) was preventing ctype_digit from working

[jatar_k]

>> (int)

you should never (I've only used it once in a production script) need to typecast vars in php, even though types are fluid in php they work well. If you are always sure what type of data you are passing around you'll be ine.

As you can see with your example, you created a situation where you changed data before you tested it which gave wrong results.

and my apologies, I saw that when I first read this thread and should have said something.

[Psychopsia]

it doesnt work if enter the number 10 in any of the fields

Sorry, was a mistake in the pattern, should be:

if (preg_match('/^\d+$/', $nextq) && preg_match('/^\d+$/', $weight))

\d+$ --- not \d$