Quick PHP question

I'm storing an operator, as in '+' or '-', in a variable. For example '$operator = "-"'. I would like to do something like this:

$operator = "-";
$numone = 5;
$numtwo = 5;
$answer = $numone $operator $numtwo;

PHP:

Obviously this doesn't work, but I would like to know how it could. Thanks in advance!

 

Try:

$answer = $numone.$operator.$numtwo;

PHP:

 

Also add

echo "<br /> Answer is ".$answer;

PHP:

to display the answer

 

It displays it properly but it doesn't subtract it. So, in this example

$operator = "-";
$numone = 5;
$numtwo = 5;
$answer = $numone.$operator.$numtwo;
echo $answer;

PHP:

it echos '5 - 5' instead of '0'. I need it to read "-" as an operator.

 

$operator = "-";
$numone = 5;
$numtwo = 5;
$answer = eval("return($numone $operator $numtwo);");
echo $answer;

 

This Works.

REMOVED :D
?>

PHP:

 

OK thanks, I got it working.

 

Works if the operator is - or +. eval handles * and / as well.

 

^^Hmm........I forgot that.......plz don't use my method, use Shallowink's

 

I would probably lean towards eval since it will handle any mathematical operator (%^/+-* etc...).

If you don't need every function, I would definitely not use eval, because it is potentially a resource heavy function and it can be a security concern.

 

I have always heard eval was risky and resource hungry, but is there another way to do that without using eval?
rohan_shenoy 's method would work if you knew the operations but eval would be better. Less code etc.