PHP Math String?

[miffe]

Say, I have a string with a math function, just divisions, multiplications, sums and substractions... and I have an integer..$b = 5;$a = "/2+4";Is there any way to make $c = $a (operations in $ ?I guess I could write a function to trim the string and detect every single character and then do the maths and return the values, but it would take me ages :\ does anyone have any preset function or an "include" ? Thank you :)Miffe

[jhecht]

Why not just use PHP to do the math, WITHOUT the strings?

[aspnetguy]

use eval

//example$a = "1+1";$b = eval($a);  //$b = 2

[miffe]

use eval

//example$a = "1+1";$b = eval($a);  //$b = 2

thanks

[miffe]

use eval

$subtotal = Round($modls[$y][17] + ($modls[$y][18]+($modls[$y][19]*$modls[$y][4])));$semitotal = $subtotal . $operaciones;echo "<tr><td>" . $semitotal . "</td></tr>";$total = eval($semitotal);$modls[$y][20] = $total;

The result from that echo (debug) is:0/11/12/14/129/1149/2(It is part of a loop of numbers... it should, theorically, work shouldn't it?)

[justsomeguy]

Whatever you send to eval needs to be a legal PHP statement. That means it needs to end with a semicolon and follow all the other rules that you would normally use.

[miffe]

Whatever you send to eval needs to be a legal PHP statement. That means it needs to end with a semicolon and follow all the other rules that you would normally use.

Yeah I checked out http://www.php.net/evalbut even so I don't understand what I have to do in my case... it's too complex for my understanding the use of the \'s and things. I just wanted to evaluate a string math operation and get a variable result :\

[miffe]

Yeah I checked out http://www.php.net/evalbut even so I don't understand what I have to do in my case... it's too complex for my understanding the use of the \'s and things. I just wanted to evaluate a string math operation and get a variable result :\

Here's my code, yes it is giving me the total, lets say for example the first product has a $subtotal of $147 when $operaciones is /1but it keeps having $147 even though $operaciones is (147)*0.85+1.2

		  $subtotal = Round($modls[$y][17] + ($modls[$y][18]+($modls[$y][19]*$modls[$y][4])));		  $semitotal = strval($subtotal) . $operaciones;		  eval("\$total = \"$semitotal\";");		  $modls[$y][20] = $total;

[justsomeguy]

You're putting the semitotal in quotes in the string. That is still making a string, not executing the code.Echo the line of code that you are sending to eval. If you can run that line of code on its own, then it will work. If you get a syntax error when you try to run the code, then you'll get the same error if you use eval to run it.

[miffe]

Here's my code, yes it is giving me the total, lets say for example the first product has a $subtotal of $147 when $operaciones is /1but it keeps having $147 even though $operaciones is (147)*0.85+1.2

		  $subtotal = Round($modls[$y][17] + ($modls[$y][18]+($modls[$y][19]*$modls[$y][4])));		  $semitotal = strval($subtotal) . $operaciones;		  eval("\$total = \"$semitotal\";");		  $modls[$y][20] = $total;

perfect, thanks a lot...that seems to have worked * solved *