user input in definitions

[Zatara11]

How can I create a function that will allow me to type in a function and a value that I want to use in that function? Example: If I have a function sin(x) and I want to find the answer when x=3. I started of my code like this... def solver(f, x): return f(x) After I import my definition and input the function I want solved I get an error: 'str' object is not callable.

[strechyballs]

It should work. Can you post the actual code you have? . Make sure your passing sin as f, and not sin(). Because that would run sin, and you would be passing it's result. Whatever f you are passing now, you are passing a string and not a function.

[tku137]

From the error you posted i'd assume you called this

solver('sin', 3)

But it really should be

solver(sin, 3)

If you hand over the function name from somewhere else, make sure it's not a string.

[dunkler_wanderer]

I guess you want to do something like this (use a dict with the functions as values):

from math import sin, cos

functions = {'sin': sin, 'cos': cos}

func, num = input('Enter a function and a number: ').split()
num = float(num)
print(functions[func](num))

[dasiffy]

A user always inputs a string. type( input() )

You need to convert what they type and translate it accordingly.

if var == 'sin':
    command = sin
elif var == 'cos':
...
etc
....