replace

[leena]

Hello,

if I have:

$theStatFormula=(&Stat1 /&Stat2);

and I want to make it:
$theStatFormula=($Stat1/$Stat2);

I tried this:
$string = ereg_replace("&",'$',trim($theStatFormula));
$string = ereg_replace(" ",'',trim($string));
$valueOfFormula=$string;

print"s:$valueOfFormula";

I get:
s🙁$Stat1/$Stat2)

But I want it to actually substitute the value of $Stat1 and $Stat2 into the equation and give me the answer for $valueOfFormula.

Why doesn't this work??

Thank you for you time. Any help is greatly appreciated.

[frigidman]

I'm sort of curious. Why don't you do:

To display the formula with values substituted:

$theStatFormula = "($Stat1/$Stat2)";
echo $theStatFormula;

To actually PERFORM the formula and get a result:

$theStatFormulaResult = ($Stat1/$Stat2);
echo $theStatFormulaResult;

If you have the & version of the string you can only work with, then this (note the importance of single and double quotes) (this evals the formula with the replaced elements and returns the result of the formula):

$originalStatFormula = '(&Stat1/&Stat2)';
$evalStatFormula = '$theStatFormula = \''.str_replace('&','$',$originalStatFormula)."';";
eval($evalStatFormula);
echo $theStatFormula;

I think one of those will cover what you are trying to do?

[frigidman]

Oh, if you wanted to display JUST the formula with the values in the formula itself and NOT execute the formula, then replace the one line for evalStatFormula with:

$evalStatFormula = '$theStatFormula = "'.str_replace('&','$',$originalStatFormula).'";';

Again, note the single and double quotes. You may need to copy paste to an editor to notice them... when they run together, it looks like a ton of single quotes... hehe.

[leena]

Hello,

Sorry I put this into my code:
$evalStatFormula = '$theStatFormula = "'.str_replace('&','$',$theStatFormula).'";';

print"esf:$evalStatFormula";

and this is what it prints:

esf:$theStatFormula = "($StandingGF /$StandingGA )";

this is not right either.

Thanks.

[frigidman]

Sorry, you need all of the code to do that one I meant. Here is the full stuff to paste:

To execute the formula and display result:

$originalStatFormula = '(&Stat1/&Stat2)';
$evalStatFormula = '$theStatFormula = \''.str_replace('&','$',$originalStatFormula)."';";
eval($evalStatFormula);

or
To display just the formula with values in place:

$originalStatFormula = '(&Stat1/&Stat2)';
$evalStatFormula = '$theStatFormula = "'.str_replace('&','$',$theStatFormula).'";';
eval($evalStatFormula);

[leena]

Hello again,

I'm sorry, I do not see how the first bit of code is different than the second. It does not seem to evaluate my equation.

This is what I have:

$StandingGF=5;
$StandingGA=2;

$originalStatFormula = '(&StandingGF/&StandingGA)';
$evalStatFormula = '$theStatFormula = \''.str_replace('&','$',$originalStatFormula)."';";
eval($evalStatFormula);

print"s:$theStatFormula";

but it only prints this:
s🙁$StandingGF/$StandingGA)

it doesn't print the answer:
s:2.5

I'm sorry if i'm frustrating you. I have no idea why this will not work.

Thanks so much for your time. Do you have any idea why this still does not work?

[frigidman]

There is a big difference between the two actually... due to the nature of double and single quotes with variables.

The first one:

$originalStatFormula = '(&Stat1/&Stat2)';
$evalStatFormula =
'$theStatFormula = \''.str_replace('&','$',$originalStatFormula)."';";
eval($evalStatFormula);

Is actually perfoming this:

$theStatFormula = '($Stat1/$Stat2)';

Single quotes around variables makes them NOT evaluate. So you get the result of:

($Stat1/$Stat2)

The second one:

$originalStatFormula = '(&Stat1/&Stat2)';
$evalStatFormula =
'$theStatFormula = "'.str_replace('&','$',$theStatFormula).'";';
eval($evalStatFormula);

Is actually perfoming this:

$theStatFormula = "($Stat1/$Stat2)";

Double quotes around variables makes them DO evaluate. So you get the result of:

(5/2)

Now, you want to actually get the value of that ? What 5 divded by 2 is? Ok, then use this third way instead:

$originalStatFormula = '(&Stat1/&Stat2)';
$evalStatFormula =
'$theStatFormula = '.str_replace('&','$',$theStatFormula).';';
eval($evalStatFormula);

Is actually perfoming this:

$theStatFormula = ($Stat1/$Stat2);

Which will result in the answer being stored into $theStatFormula.

See, its all a sticky situation with them single and double quotes. Total different behavior happens depending on what you do with them. The whole reason I have the "eval()" function in the mix, is because you wanted to take the formula, and turn it into something that executes with variable names. Since variable names get stored inside the string, you have to 'execute' the string somehow. but to get a result, you build the full PHP line code to do it (includeing the semicolon at the end). "eval()" is a really fun function once you get to know it... it can allow for some seriously dynamic coding, like this case you are doing with custom built and executed formulas!

Hope this is a bit more clear? I'm sorry I didnt break this up like this before... was sort of in a rush.

[leena]

Thank you so much. It's working now.

That is really confusing (with all the quotes and stuff).

Thanks again!