doing math with a string

Question

Possible Duplicate:
PHP String Calculation

I am trying to make a 24-game solver.

Can i do something like this?:

$x = '*';
$a = 1;
$b = 2;

$sum = $a $x $b; //Trying something like this
$sum = $a * $b; //Actual sum

if($sum == $result) echo 'Hello World!';

Or $x as an array.

It's so confusing.

fyi, a "sum" is only when you add two numbers. If you multiply two numbers, it's a "product." Or just "the result." — octern, Mar 12 '12 at 01:29

fred2 · Accepted Answer · 2012-03-12T01:07:23.447

2

Are you sure you want to do that?

Why not:

$x = '*';
$a = 1;
$b = 2;

$sum1 = $x == '*' ? $a * b : false;
$sum2 = $a * $b;

if($sum1 == $sum2) echo 'Hello World!';

That'll have the same effect, without trying to eval a string.

edited Mar 12 '12 at 01:07

answered Mar 12 '12 at 00:47

fred2

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thanks can use a switch, stupid me ;p – peterdoesco.de Mar 14 '12 at 11:39

score 0 · Answer 2 · edited Mar 12 '12 at 00:48

0

The easiest way is to use eval which lets you execute a php string. Read the CAUTION section on that page though: do not to pass any user provided data into it.

edited Mar 12 '12 at 00:48

Vyktor

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answered Mar 11 '12 at 23:47

C.Evenhuis

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doing math with a string

2 Answers2