Convert a string to a variable

[stdq]

Hi, everyone. So, suppose I have a variable holding a string, like

$var = "ln(x)";

I wanna be able to numerically integrate that string - I wanna be able to, inside a for statement, calculate ln(x) for some values of x. How do I make PHP understand the value of the string as a statement? Thanks in advance!

[stdq]

Nevermind, achieved that using eval. Thanks again!

[Rabbit]

Be careful with eval. If you are allowing a client to determine what goes into that eval, they can do a lot of harm to your server by running any code they want.

[stdq]

Thanks! I guess then I will have to remove a functionality from my website. Is there another option?

[Rabbit]

That depends on what you actually want to do. If you just want return ln from an input number, then there's no need to use eval, you can just call the function directly.