very simple question

[mysterbx]

How can i make this result: "12-1" to output like this: "11" ?

 

In other words:

I get this result from my script: 12-1

I need to make the script do the match: 12-1=11, so the $result would be 11

[obsidian]

If I understand properly, you are retrieving the string value of "12-1" and you need to execute that equation rather than displaying it to the screen. If this is the case, you will either need to build a parser of some sort (safer) or use eval() to execute the equation (easier but more dangerous):

 

<?php
$eq = "12-1";
eval("\$result = $eq;");
echo $result;
?>

[mysterbx]

yeap that works great!

[btherl]

obsidian hinted at this, but don't put that code out for public use!  It will allow your users to execute any command they want on your webserver.

 

You can avoid this by sanitizing the input, for example:

 

$safe_eq = preg_replace('|[^[:digit:]()+*/-]|', '', $eq);

 

That will allow only digits and the following symbols: ( ) + * / -

 

I think that ought to be safe.. at least I can't imagine anything you could do with that other than causing the eval to fail due to syntax error.

[mysterbx]

code is for timed backups...

It gets the time, then gets the timezone.

 

And the output is: 15(time)-5(timezone), in otherwords: 15-5

 

and I needed a code that "does the math"

 

the command runs in background, so no publick use will be allowed...

[obsidian]

code is for timed backups...

It gets the time, then gets the timezone.

 

And the output is: 15(time)-5(timezone), in otherwords: 15-5

 

and I needed a code that "does the math"

 

the command runs in background, so no publick use will be allowed...

 

If that's the case, I would recommend you do something like this (I'm one to always go above and beyond on precautions):

<?php
// since you know it will always be [digits] + or - [digits], this will work:
function parseTime($string)
{
  if (!preg_match('|^([\d]+)(+|-)([\d]+)$|', $string, $match))
  {
    // Invalid format presented
    return FALSE;
  }

  switch ($matches[2])
  {
    case '+':
      return intval($matches[1]) + intval($matches[3]);
      break;

    case '-':
      return intval($matches[1]) - intval($matches[3]);
      break;
  }
}
?>

 

Hope this makes sense.

[mysterbx]

that works... 10x!