After a lot of operations I've got some like:
$exr = "2+3/1.5";How I can get result of this expression? Like this:
$result = (floatval)$exr; // show: 4Of course it doesn't work. I've got only 2, first symbol. Any easy way to solve this?
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6 Answers
You can use the PHP eval function like this:
$exr = '2+3/1.5';
eval('$result = ' . $exr . ';');
var_dump($result);
// float(4)
Read this note carefully:
Caution: The eval() language construct is very dangerous because it allows execution of arbitrary PHP code. Its use thus is discouraged. If you have carefully verified that there is no other option than to use this construct, pay special attention not to pass any user provided data into it without properly validating it beforehand.
Eval is EVIL
I dont know why every answer here is telling you to do this? But avoid using this.
Here is very good function that can do the same without the eval() Source
function calculate_string( $mathString ) {
$mathString = trim($mathString); // trim white spaces
$mathString = ereg_replace ('[^0-9\+-\*\/\(\) ]', '', $mathString); // remove any non-numbers chars; exception for math operators
$compute = create_function("", "return (" . $mathString . ");" );
return 0 + $compute();
}
Use it as
$exr = '2+3/1.5';
echo calculate_string($exr);
1 Comment
Max
Good idea! But need to correct regex a little bit. Cause in math available also cos, sin, pow, etc.
2 Comments
Max
Thanks a lot. I can't understand how "googling" with that question?! Bad English :)
JMax
You could try this query or see Salman comment's on the accepted answer :)
Try:
$exr = "2+3/1.5";
echo eval("return $exr;"); //shows 4
Comments
You could use eval.
$result = eval($exr);
Comments
The easiest way would be to just run it through eval(), but that is very insecure. For security I'd recommend to filter certain characters, like a-z and special chars like ";:'.
