Simple ereg example not working

mottwsc

I've used more complex ereg filters before, but for some reason, the one below is allowing a three-digit number to pass. It should only allow a single-digit number to pass (that is what I'm testing for). I've tried both variations, but neither works. Is there something simple I'm missing?

Version 1:

$answer = 140;
echo "answer:".$answer." ";
if(!ereg("^{([0-9]{1})+$",$answer))}
{echo "failed ";}
else
{echo "passed ";}

Version 2:

$answer = 140;
echo "answer:".$answer." ";
if(!ereg("^{([0-9]{1,1})+$",$answer))}
{echo "failed ";}
else
{echo "passed ";}

WeAnswer_IT

It's that + sign you have before the $ sign. It says "allow ONE or MORE of the previous group".

Your regex is saying this, in English: "From beginning to end, find any length of a string that is comprised of single digits, 0-9."

If you take away the plus sign, it's saying: "From beginning to end, find any length of a string that is comprised of one digit, 0-9."

Note that your parenthesis are not necessary, but are not doing any harm, and also that you are passing an integer to ereg as its second argument. You should make it a string first, because ereg expects strings. This wouldn't create an error or anything, but it's good practice.

$answer = 140;
$answer = strval($answer);
echo "answer: ".$answer."<br />";
if( ereg("^[0-9]{1}$", $answer) )
{
    echo "passed<br />";
}
else
{
    echo "failed<br />";
}

mottwsc

That worked...

Thanks so much!

laserlight

You should not use regex for this. Use [man]ctype_digit/man instead:

$answer = 140;
echo "answer: ".$answer."<br />";
if (strlen($answer) == 1 && ctype_digit($answer))
{
    echo "passed<br />";
}
else
{
    echo "failed<br />";
}

If you do want to use regex, then use the PCRE functions instead of the ereg family of regex functions, e.g.,

$answer = 140;
$answer = strval($answer);
echo "answer: ".$answer."<br />";
if (preg_match('/^\d$/', $answer))
{
    echo "passed<br />";
}
else
{
    echo "failed<br />";
}

mottwsc

Thanks for your additional advice.

laserlight

You're welcome, and remember to mark this thread as resolved (if it is) using the thread tools.

Kudose

Just to further Laserlight's point, the ereg* functions will most likely be leaving in PHP6.