How to replace the string using strrep?

 say I have a str = 'f(x) = 2*x^3' or 'fun(var_name) = 2*var_name^3'
 and I have a value of 3(val = 3)

how do I make sure that the strrep will replace the x value or var_name with the value that I want?

Answer 1

[Star Strider]

I am not certain what you want to do, but if you want to make functions out of your expressions, use the Anonymous Functions syntax:

f = @(x) 2*x.^3;

then call them as you would any other function:

var_name = 5;
result = f(var_name)

produces:

result =

     250

[Kratos]

What I meant was I don't know the I don't know what the input is going to be it could be anything like 'fun(var_name) = 2*var_name^3' or 'fun(pos) = 2*pos^3' or 'fun(car) = 2*car^3'. anything. So how do I make sure that I am replacing the car with the value.

[Star Strider]

With ‘fun’ defined as:

fun = @(x) 2*x.^3;

the result for each of those would be:

result = fun(var_name)
result = fun(pos)
result = fun(car)

The function takes care of replacing the value appropriately. To understand how functions work, please see the documentation for ‘Anonymous Functions’ that I provided the hyperlink to in my Answer.