Hello all,

I'd like to check on a php page that a text string complies with the following rule : Contain numbers,  in ascending order, with only   ,    or    -     as separators

The numbers represent requested items (like pages to print), my purpose is then to count the number of item requested.

 1,3,5-6 : Match (4 items)

1,5,10-12,15,25-30,55 : Match (13 items)

1,5-4,7 : No Match (not ascending order)

Any other caracter but 0123456789,-   no match

 

Thanks.

 

I refer you the this article http://regexadvice.com/blogs/mash/archive/2007/06/01/Are-you-ready-for-regex_3F00_.aspx because it seems to me from your question you are under the impression regex do something they don't.  Regexes don't understand context of your data, which is counting numbers.  Aside from testing the allowable characters, your last sentence, everything else in outside the realm of using a regex.

You could mimic the ascending value but from your samples it would be unrealistic do so for your problem, since to do so you would have to have an upper bound and even that would be unwieldy.

---

Michael

"In theory, theory and practice are the same. In practice, they are not."
Albert Einstein

It requires a bit more than just regex, but this worked for me (note that it finds the first "items" string and then checks if it's valid, if an error is found it returns 0 as the page count).

If you happen to want to match "items" string that might contain only one number/range you will need to identify what's bordering the "items" string because currently this method requires at least 2 numbers/ranges separated by commas. 

<?php
function countpages($string) {
  if (preg_match('/(?:(?:\d+-\d+|\d+),)+(?:\d+-\d+|\d+)/',$string,$result)) {
    $checkone=preg_split('/,|-/',$result[0]);
    for ($h = 0; $h < count($checkone)-1; $h++) {
      if ($checkone[$h]>=$checkone[$h+1]) {
        return 0;
      }
    }
    preg_match_all('/(\d+)-(\d+)/',$result[0],$ranges);
    $count=count($checkone)-(count($ranges[0])*2);
    for ($i = 0; $i < count($ranges[0]); $i++) {
      $count=$count+($ranges[2][$i]-$ranges[1][$i]+1);
    }
    return $count;
  } else {
    return 0;
  }
}
echo '<pre>';
echo '1. pages:'.countpages(' 1,3,5-6 : Match (4 items)').'<br>';
echo '2. pages:'.countpages('1,5,10-12,15,25-30,55 : Match (13 items)').'<br>';
echo '3. pages:'.countpages('1,5-4,7 : No Match (not ascending order)').'<br>';
echo '4. pages:'.countpages('Any other caracter but 0123456789,-   no match').'<br>';
echo '5. pages:'.countpages(' 3,3-5 : No Match (duplicates)').'<br>';
?>

---

Thanks for the help "mash" but It seams my poor english has mislead you regarding my purpose...

I am not counting on regex to actually count my datas, I would like to use it to check the format of the submitted data before starting to process them since if they are not correct the process might have very bad results.

 

To "ddrudik" :

Thanks to you too, that's more the kind of answer I am looking for.

I think I will manage to work with it in order to achieve my purpose.

I think I'm donen with it :

I added a numeric test in case the string is just a number.

And also a part so that if there is not comma in the string I check the range.

Thanks again !

Here is "final" function :

countitems($string) {
        // Check if string is numeric
        if (is_numeric($string)){ 
        return 1; 
        } 
        // check if numbers are in ascending orders
        $checkorder=preg_split('/,|-/',$string);
        for ($h = 0; $h < count($checkorder)-1; $h++) {
                if ($checkorder[$h]>=$checkorder[$h+1]) {
                        return 0; 
                } 
        } 
        // check if range/digit comma range/digit
        if (preg_match('/(?:(?:\d+-\d+|\d+),)+(?:\d+-\d+|\d+)/',$string,$result)) {
                preg_match_all('/(\d+)-(\d+)/',$result[0],$ranges); 
                $count=count($checkorder)-(count($ranges[0])*2); 
                for ($i = 0; $i < count($ranges[0]); $i++) { 
                        $count=$count+($ranges[2][$i]-$ranges[1][$i]+1); 
                } 
                return $count; 
        }
        // check if range
        if (preg_match('/(\d+)-(\d+)/',$string,$result)){ 
                preg_match_all('/(\d+)-(\d+)/',$result[0],$ranges); 
                $count=count($checkorder)-(count($ranges[0])*2); 
                for ($i = 0; $i < count($ranges[0]); $i++) { 
                        $count=$count+($ranges[2][$i]-$ranges[1][$i]+1); 
                } 
                return $count; 
        } 
        // if other case
        return -1;
}

That's quite a bit more complicated than my function, but if that's what you are looking for...

---